Role of mRNA termination in regulation of ermK

To study the role of mRNA termination in the regulation of ermK, we introduced mismatches into terminators by in vitro mutagenesis. In wild-type ermK, only truncated transcription products were detected in the absence of induction. In contrast, only the full-length transcript was synthesized in the terminator 1 and terminator 2 double mutants, even in the absence of erythromycin. These results indicate that the expression of ermK is primarily regulated by transcriptional attenuation rather than translational attenuation. We also tested the possible contribution of translational attenuation control to the regulation of ermK by constructing a triple mutant (terminator 1 plus terminator 2 plus the methylase Shine-Dalgarno region). A higher level of beta-galactosidase synthesis was seen in the triple mutant. Therefore, unlike with previously described attenuators, it can be concluded that both transcriptional and translational attenuation contribute to the regulation of ermK, although transcriptional attenuation plays a larger role.

Ideal timing of pediatric laryngotracheal reconstruction

OBJECTIVE

To determine whether there is an ideal age at which to perform a laryngotracheal reconstruction (LTR) in the pediatric population.

DESIGN

Prospective observational study.

SETTING

Tertiary care children's hospital.

PATIENTS

Forty-eight patients aged 48 months or younger with laryngotracheal stenosis who underwent 50 LTRs from October 1, 1986, to June 30, 1995. Patients were divided into 2 groups: group 1, aged 8 through 24 months (22 patients); group 2, aged 25 through 48 months (26 patients).

INTERVENTION

Endoscopy and LTR.

MAIN OUTCOME MEASURES

Successful decannulation.

RESULTS

Statistical analysis showed that (1) patients in group 2 had more severe degree of laryngotracheal stenosis as determined by duration of stenting with no difference in multiple sites of stenosis or type of repair required to correct laryngotracheal stenosis and (2) patients in group 2 were more likely to have successful decannulation.

CONCLUSION

Laryngotracheal reconstruction at a younger age (< 25 months) is important for a child's speech and language development as well as for eliminating the morbidity and mortality associated with a tracheotomy. However, LTR at a younger age is associated with a higher risk of failure despite lesser degree of pathology. Therefore, although we still recommend LTR at a younger age since it may be beneficial for a child's speech and language development and avoidance of tracheotomy complications, this recommendation may be at the price of LTR failure and requirement for revision procedures.

A bacterial artificial chromosome-based framework contig map of human chromosome 22q

We have constructed a physical map of human chromosome 22q using bacterial artificial chromosome (BAC) clones. The map consists of 613 chromosome 22-specific BAC clones that have been localized and assembled into contigs using 452 landmarks, 346 of which were previously ordered and mapped to specific regions of the q arm of the chromosome by means of chromosome 22-specific yeast artificial chromosome clones. The BAC-based map provides immediate access to clones that are stable and convenient for direct genome analysis. The approach to rapidly developing marker-specific BAC contigs is relatively straightforward and can be extended to generate scaffold BAC contig maps of the rest of the chromosomes. These contigs will provide substrates for sequencing the entire human genome. We discuss how to efficiently close contig gaps using the end sequences of BAC clone inserts.

Prostaglandin-E2 regulation of tumor necrosis factor receptor release in human monocytic THP-1 cells

Recent in vitro studies indicate that tumor necrosis factor (TNF) production in human monocytic THP-1 cells is suppressed by action of arachidonic acid metabolite prostaglandin-E2 (PGE2). PGE2 stimulation of human monocytic cell line THP-1 demonstrates that PGE2 not only regulates TNF activity at production levels, but does so through the release of two soluble TNF receptors (BP-55, BP-75) as well. PGE2 can thus exert a regulatory effect on TNF biologic activity by interfering with its ability to reach cell membrane receptors. THP-1 cells were activated with PGE2 for either 2- or 6-hr time periods, and the supernatants subsequently tested by ELISA to quantitate the levels of soluble receptor released. In addition, we examined mechanisms of receptor shedding by investigating the rate of membrane internalization and the role of serine proteases. PGE2-stimulated THP-1 cells showed soluble 55- and 75-kDa TNF receptor release levels which exceeded that of spontaneous release at both 2- and 6-hr activation periods. The numbers of both membrane TNF receptors were significantly upregulated as well in PGE2-activated cells, whereas the levels of 55- and 75-kDa TNF receptor mRNA levels remained unchanged. Thus, PGE2 induces TNF receptor release primarily at posttranscriptional levels. Inhibition of serine proteases with Pefabloc, a phenylmethylsulfonyl fluoride analog, resulted in the inhibition of both spontaneous and PGE2-stimulated release. Treatment of THP-1 cells with N-ethylmaleimide and low-temperature incubation, both known to block membrane internalization, also blocked spontaneous and PGE2-induced release. Internalization and cleavage by protease are therefore critical factors in PGE2-induced release of soluble TNF receptor shedding.

Speaking clearly for the hard of hearing IV: Further studies of the role of speaking rate

The contribution of reduced speaking rate to the intelligibility of "clear" speech (Picheny, Durlach, & Braida, 1985) was evaluated by adjusting the durations of speech segments (a) via nonuniform signal time-scaling, (b) by deleting and inserting pauses, and (c) by eliciting materials from a professional speaker at a wide range of speaking rates. Key words in clearly spoken nonsense sentences were substantially more intelligible than those spoken conversationally (15 points) when presented in quiet for listeners with sensorineural impairments and when presented in a noise background to listeners with normal hearing. Repeated presentation of conversational materials also improved scores (6 points). However, degradations introduced by segment-by-segment time-scaling rendered this time-scaling technique problematic as a means of converting speaking styles. Scores for key words excised from these materials and presented in isolation generally exhibited the same trends as in sentence contexts. Manipulation of pause structure reduced scores both when additional pauses were introduced into conversational sentences and when pauses were deleted from clear sentences. Key-word scores for materials produced by a professional talker were inversely correlated with speaking rate, but conversational rate scores did not approach those of clear speech for other talkers. In all experiments, listeners with normal hearing exposed to flat-spectrum background noise performed similarly to listeners with hearing loss.

Transaxillary minithoracotomy versus video-assisted thoracic surgery for spontaneous pneumothorax

BACKGROUND

Although management of spontaneous pneumothorax by video-assisted thoracic surgery (VATS) has generally shown superior clinical results to thoracotomy, management of spontaneous pneumothorax by transaxillary minithoracotomy (TAMT) has also shown good clinical results. The objective of this study was to compare the clinical results of VATS and TAMT in treating spontaneous pneumothorax.

METHODS

Sixty-six patients, aged 13 to 81 years, with recurrent, persistent or contralateral spontaneous pneumothorax were involved in this study. Thirty-six patients were treated by VATS and 30 by TAMT. The operating time, the amount of analgesics used on the first postoperative day, the duration of the indwelling chest tube, and the number of recurrences after operation were compared. The follow-up periods of both procedures were from 6 to 24 months.

RESULTS

Of the 66 patients, 64 were male and 2 were female. The duration of operation, from start of skin incision to insertion of chest tube, was 91.2 +/- 36.8 minutes in VATS and 86.3 +/- 40.9 minutes in TAMT (p = 0.6061). The amount of analgesics (keptoprofen) used was 1.9 +/- 2.3 ampules in VATS and 2.1 +/- 2.9 ampules in TAMT (p = 0.0883). The duration of indwelling chest tube was 5.0 +/- 4.0 days in VATS and 4.3 +/- 2.1 days in TAMT (p = 0.3707). The number of recurrences after operation was 4 in VATS and none in TAMT.

CONCLUSIONS

There were no advantages of VATS over TAMT for management of recurrent, persistent, or contralateral spontaneous pneumothorax in regard to the operating time, the amount of analgesics used on the first postoperative day, the duration of the indwelling chest tube, and the number of postoperative recurrences in patients with apical bullae.

Laryngomalacia. The search for the second lesion

OBJECTIVES

To determine the necessity of rigid endoscopy in the diagnosis and management of laryngomalacia and its associated synchronous airway lesions (SALs), to analyze the incidence of SALs associated with laryngomalacia and their significance, and to determine the need for epiglottoplasty in management of laryngomalacia.

DESIGN

Retrospective medical chart review.

SETTING

Tertiary care children's hospital.

PATIENTS

Two hundred thirty-three patients with a primary diagnosis of laryngomalacia on flexible fiberoptic laryngoscopy treated at the Children's National Medical Center, Washington, DC, from January 1, 1984, to June 30, 1994.

INTERVENTION

Evaluation and treatment of laryngomalacia and associated SAL by flexible fiberoptic laryngoscopy, radiographic studies, rigid endoscopy, and other surgical procedures.

MAIN OUTCOME MEASURES

Resolution of airway symptoms from laryngomalacia and associated SAL.

RESULTS

Ninety patients (38.6%) underwent rigid endoscopy, and 12 patients (5.2%) required epiglottoplasty. Synchronous airway lesions were discovered in 44 patients (18.9%). Eleven patients (4.7%) had SALs that wre considered clinically significant; nine (3.9%) of these required surgical intervention.

CONCLUSIONS

Rigid endoscopy in evaluation of an infant with laryngomalacia is rarely necessary. Clinically significant SALs requiring surgical intervention are uncommon. Surgical intervention for laryngomalacia also is rarely necessary.

The effect of gastroesophageal reflux on laryngotracheal reconstruction

OBJECTIVES

To determine the need for preoperative evaluation for gastroesophageal reflux disease (GERD) in all children undergoing laryngotracheal reconstruction (LTR) and to assess the effect of GERD on the outcome of LTR.

DESIGN

Prospective, single-blind observational study.

SETTING

Tertiary care children's hospital.

PATIENTS

Seventy-four pediatric patients with laryngotracheal stenosis who underwent LTR at the Children's National Medical Center, Washington, DC, from October 1, 1986, through August 31, 1994.

INTERVENTION

Evaluation for and treatment of GERD, LTR, endoscopy, and removal of granulation tissue.

MAIN OUTCOME MEASURES

Successful decannulation and number of endoscopies required to remove laryngeal and tracheal granulation tissue.

RESULTS

Seventy-four patients underwent 82 LTRs. The senior surgeon was blinded to the status of GERD evaluation and treatment. Four groups were identified: 37 patients (40 LTRs) with no preoperative evaluation for GERD; 10 patients (11 LTRs) with normal findings on preoperative evaluation for GERD; seven patients (nine LTRs) with abnormal findings on preoperative evaluation for GERD but who failed to receive appropriate treatment; and 20 patients (22 LTRs) with abnormal findings on preoperative evaluation for GERD who received appropriate therapy. Severity and extent of stenosis as determined by multicentricity of stenosis, type of repair, and duration of stent were similar in the four groups. The effect of GERD and its treatment on the outcome of LTR was measured by the number of endoscopies necessary for removal of granulation tissue following reconstruction and successful decannulation. Statistical analyses indicate that (1) all children do not require preoperative evaluation for GERD; (2) neither the presence of GERD nor its treatment are major factors in determining the outcome of LTR.

CONCLUSION

Preoperative evaluation for GERD and its treatment do not favorably affect the outcome of LTR.

Single-mode GaAs/AIGaAs W waveguides with a low propagation loss

We have designed a low-loss single-mode GaAs/AIGaAs optical waveguide with a symmetric five-layer heterostructure at the 1.31-µm wavelength by use of an effective-index method. Waveguides with a W-shaped refractive-index profile have been grown by use of a metallo-organic chemical vapor deposition technique and fabricated with a chemical wet-etching method. Propagation loss has been measured by use of the Fabry-Perot resonance method and a sequential-cleaving experiment. The measured loss is as low as 0.19 dB/cm for waveguides with 2.3-µm thickness and 4.3-µm width, which is comparable to the lowest-loss semiconductor waveguides yet reported. These waveguides could be used to make low-loss modulators for guided-wave devices.

A novel Bcl-2 related gene, Bfl-1, is overexpressed in stomach cancer and preferentially expressed in bone marrow

Programmed cell death (apoptosis) is an active process which is genetically encoded and plays an important role in several cellular activities such as embryonic development, deletion of autoreactive T-cells and homeostasis. Several genes regulating apoptosis have been reported, including p53, one of the tumor suppressor genes, c-myc, one of the proto-oncogenes, and various kinds of Bcl-2 related genes. A new cDNA clone which is homologous to Bcl-2, named as Bfl-1 were isolated from a human fetal liver at 22 week of gestation. This clone was identified by computer analysis of random cDNA sequences that were obtained in an effort to expand the expressed sequence tag (EST) databases to be used for human genome analysis. The homology was recognized by 72% amino acid identity to the murine A1 gene, a member of the Bcl-2-related genes. The homology to the BH1 and BH2 domains of Bcl-2 was especially significant, suggesting that Bfl-1 is a new member of the Bcl-2-related genes. Bfl-1 is abundantly expressed in the bone marrow and at a low level in some other tissues. Interestingly, a correlation was noted between the expression level of Bfl-1 gene and the development of stomach cancer in eight sets of clinical samples. It is conceivable that Bfl-1 is involved in the promotion of the cell survival in the stomach cancer development or progression.

Invasive Aspergillus sinusitis in pediatric bone marrow transplant patients. Evaluation and management

OBJECTIVES

To evaluate the following: the incidence of invasive Aspergillus sinusitis (AS); the value of surveillance nasal cultures and screening radiologic studies in predicting AS; the clinical criteria used to decide on surgical biopsy in patients suspected of having AS; the surgical and medical management of AS; and the outcome of AS in the peritransplantation period of children who underwent bone marrow transplantation.

DESIGN

Retrospective medical chart review.

SETTING

Tertiary care children's hospital.

PATIENTS

Eighty pediatric patients who underwent bone marrow transplantation for a variety of refractory malignant neoplasms or lymphohematopoietic disorders at the Children's National Medical Center, Washington, DC, from April 1, 1988, to September 30, 1993.

INTERVENTION

Diagnostic surgical biopsies, surgical débridement, and treatment with amphotericin B.

MAIN OUTCOME MEASURE

Resolution of AS and discharge from the hospital.

RESULTS

Seventy-two patients had screening sinus radiographs, 27 of which showed abnormalities. Aspergillus sinusitis developed in three of the patients with abnormal screening radiographs. Fifty-eight patients had screening nasal cultures. One culture was positive for Aspergillus, and histopathologically proved AS developed in this patient. Twelve diagnostic biopsies were done in nine patients. Three biopsy specimens showed histopathologic evidence of AS. The three patients with AS were successfully treated with aggressive surgical and medical therapy and were discharged from the hospital.

CONCLUSION

The incidence of AS was 4% (3/80) in the patients who underwent bone marrow transplantation. Screening radiographs, while not a good predictor of AS, have a role in evaluation of patients undergoing bone marrow transplantation to define preexisting sinus disease. Screening nasal cultures do not reliably predict AS. When AS is suspected and diagnostic biopsy is considered, the seven clinical criteria outlined in this article should be used. Survival of immunocompromised patients with AS requires early diagnosis and aggressive surgical and medical therapy.

Construction of a gene expression profile of a human fetal liver by single-pass cDNA sequencing

We have obtained an overall gene expression profile of a human fetal liver by sequencing the 5' ends of random cDNA clones from an unbiased cDNA library. As a result, many novel genes that might be related to liver growth and hemopoiesis have been identified. Poly (A)+ RNA was purified from the liver of a human fetus obtained at the 22nd week of gestation, and a directional library was constructed with oligo d(T)-primed cDNAs synthesized without any normalizing procedures. The 5' end of each randomly chosen clone was sequenced by the dideoxy-chain termination methods, and each sequence was used for homology search in the public databases such as GenBank, SWISS-PROT, and PIR. Of 1231 random cDNA clones analyzed, 697 clones representing 204 different transcripts (57%), were identical to previously known human genes. The spectrum of the genes in this category reflected well the physiological characteristics of the fetal liver, a combination of hepatic and hemopoietic functions. About 4% of the clones represented novel gene transcripts with significant homologies to known genes of human or other organisms. These included several genes that are known to be involved in cellular differentiation and/or proliferation. About 25% of the clones had no statistically significant match to any known genes. In summary, we have identified 546 different gene transcripts consisting of 204 known human genes, 42 homologous genes, and 300 unknown genes. Thus, this approach appears to be a highly efficient way to identify novel genes of biological interest.

Branchial anomalies: a review of 52 cases

Fifty-two patients with branchial anomalies (BA) treated at the Children's National Medical Center between 1983 and 1993 were reviewed to determine the incidence of different types of anomalies and to analyze the authors' method of diagnosis and management. First BA was seen in 25%, second in 40%, third in 8%, and fourth in 2%. In 25%, the origin of the anomaly was undetermined. Our incidence of first BA was significantly higher than the incidence reported in other series. Of the anomalies, sinuses were more common than cysts or fistulae. Sinuses tend to present at an earlier age than cysts, which take time to enlarge and present clinically. Repeated incision and drainage and incomplete excisions were frequently seen with first, third, and fourth anomalies due to misdiagnosis. Recent trend has been to utilize radiographic studies more frequently, and they have been found to be helpful in guiding surgical therapy, particularly with the more complicated cases.

The radial sensory nerve entrapped between the two slips of a split brachioradialis tendon: a rare aspect of Wartenberg's syndrome

A retrospective study was designed to verify how often an anatomic variation caused the radial sensory nerve entrapment at the forearm (Wartenberg's syndrome). This variation, in which the superficial branch of the radial nerve emerges from under the fascia between two slips of a split brachioradialis tendon, was mentioned once in a clinical textbook as a basis for nerve entrapment but was found to occur in 5 of 150 dissected arms in 4 of 75 cadavers (3.3% of the investigated arms) in a recent anatomic study. To evaluate the incidence of this variation, 143 operative reports from patients who had Wartenberg's syndrome were reviewed. The variation was observed in seven patients. We conclude that any operation for Wartenberg's syndrome should include a thorough investigation of the site where the radial sensory nerve emerges from under the fascia and, if the nerve emerges through a split brachioradialis tendon, the anomalous tendon slip should be divided.

Intracranial complications of sinusitis in childhood

Complications of sinusitis in children, such as intracranial abscess formation, are uncommon and are often clinically unremarkable in comparison to similar disease processes in adults. Between 1983 and 1991, 443 children were admitted to Children's National Medical Center in Washington, DC, for treatment of sinusitis. Fourteen of these children presented with intracranial extension of the infection and abscess formation. A retrospective review of these patients revealed that the risk of developing an intracranial abscess secondary to sinusitis was 3%. The management of these patients included surgical drainage of the infected sinuses and intracranial surgical exploration. Cranialization and exenteration of the frontal sinus proved to be effective single-stage procedures. While not indicated in all patients, these procedures eliminated the sinus as a source of continued or potential infection and obviated the need for a second obliterative procedure. Combined antimicrobial therapy and surgical drainage should be the management protocol.

Effect of t-butylhydroperoxide on p-aminohippurat uptake in rabbit renal cortical slices

OBJECTIVES

Oxygen free radical (superoxide radical, hydrogen peroxide, and hydroxyl radicals) have been considered to be responsible for the pathogenesis of ischemia reperfusion injury and toxic chemical injury in a variety of organs including myocardium, brain, intestine and kidneys. In in vitro models using a suspension of rat proximal tubule segments, t-butylhydroperoxide(t-BHP), a potent oxidant, induces the severity of tubular dysfunction as reflected by decreases in tubular respiration which is associated with a progressive increase in lipid peroxidation. The precise mechanism of t-BHP-induced cell injury remains to be determine. The study was carried out to determine the effect of oxygen free radicals on organic anion transport in renal proximal tubule.

METHODS

By renal cortical slices, we studied accumulation of organic ions, PAH efflux oxygen consumption, lactate dehydrogenase (LDH), lipid peroxidation. The data are expressed as the mean +/- SE and evaluated for significance using Student's t-test. A probability level of 0.05 was used to establish significance.

RESULTS

Effect of t-butylhydroperioxide(t-BHP), a potent oxidant, on organic anion p-amminohippurate(PAH) uptake was studied in rabbit renal cortical slices. t-BHP inhibited irreversibly PAH and organic cation tetraethylammonium(TEA) uptake in a dose dependent manner with IC50 of approximately 1.0 and 0.85 mM, respectively. The efflux rate constant pf PAH was not altered by the presence of 1 mM t-BHP, indicating that the inhibitory effect of t-BHP on the steady-state accumulation of PAH is due primary to the reduction in the influx of PAH across the basolateral membrane. The kinetic analysis showed that 1mM t-BHP caused a significant reduction in the maximum rate of PAH influx(Vmax) from 1.54 +/- 0.74 to 0.72 +/- 0.54 umol/g/10 min without an effect on Km, indicating that t-BHP depressed PAH influx across the basolateral membrane by reducing the number or turnover rate of active carrier for PAH transport, but not by altering substrate affinity of the carrier. Ouabain-sensitive and -insensitive oxygen consumption was not different between the control and t-BHP-treated slices. t-BHP caused an increase in LDH release and lipid peroxidation in a dose-dependent manner, which were highly correlated with changes in PAH uptake.

CONCLUSION

These results suggest that t-BHP inhibition of PAH uptake is attributed to renal tubular cell damage and lipid peroxidation plays an important role in the inhibitory effect of t-BHP on PAH transport in rabbit proximl tubules.

A randomized double-blind trial of ondansetron alone versus in combination with dexamethasone versus in combination with dexamethasone and lorazepam in the prevention of emesis due to cisplatin-based chemotherapy

OBJECTIVE

To compare the effectiveness and side effects of antiemetic regimens using ondansetron alone (O) versus ondansetron plus dexamethasone (OD) versus ondansetron plus dexamethasone plus lorazepam (ODA) in the prevention of emesis induced by cisplatin-based chemotherapy.

DESIGN

Randomized, double-blind trial.

PATIENTS AND METHODS

In this study, 75 patients who were receiving cisplatin (60 mg/m2) on day 1 and 5-fluorouracil (1,000 mg/m2) on day 2 to day 6 were enrolled. Patients were randomized to one of three treatment regimens: O, OD, or ODA. The patients assigned to O regimen received ondansetron 8 mg intravenously as a loading dose 15 minutes prior to cisplatin, then 1 mg/h continuous i.v. infusion (24 mg/day) for 48 hours. OD regimen consisted of ondansetron given as above plus dexamethasone administered at a dose of 10 mg i.v. injection every 12 hours for 3 days. ODA regimen was OD regimen plus lorazepam administered at a dose of 0.5 mg orally every 6 hours for 3 days. To ensure blinding, O group patients received 10 ml placebo-saline i.v. injection every 12 hours for 3 days, and O and OD group patients received placebo tablets orally every 6 hours for 3 days.

RESULTS

One patient did not receive assigned antiemetic regimen and was excluded from the analysis. In the acute phase, complete control of emesis was seen in 85% of all patients, and there was no significant difference among the three groups (p = .442). Complete control of nausea during the acute phase was achieved in 10 patients (41.2%) treated with O regimen alone, in 23 patients (92.0%) treated with OD regimen, and in 16 patients (64.0%) treated with ODA regimen (p < .001). In the delayed phase, 68% of patients who received the three-drug combination (ODA) and 56% of patients who received the two-drug combination (OD) obtained complete control of emesis, as opposed to 29% who were given ondansetron alone (p < .021). The incidences of headache, flushing, dry mouth, hiccups, and constipation were mild and tolerable and did not differ among the three groups.

DISCUSSION

Ondansetron was very effective in the prevention of nausea and vomiting during the acute phase after cisplatin administration. In treating delayed nausea and vomiting, although the results of three regimens were still disappointing, the combination of ondansetron plus dexamethasone or plus lorazepam provided superior results. Patients who received the lorazepam-containing regimen appeared more comfortable and less restless than those who were given other regimens.

Arytenoidectomy in children

Vocal cord paralysis is the second most common cause of stridor in early infancy, and as many as 52% of patients will not recover spontaneously. Bilateral vocal cord paralysis often requires a tracheotomy for airway distress. If resolution of the bilateral vocal cord paralysis does not allow for decannulation, arytenoidectomy is an option. A retrospective review of 30 children with bilateral vocal cord paralysis who underwent an arytenoidectomy was undertaken. An external arytenoidectomy via laryngofissure was performed in 19 patients, a laser arytenoidectomy in 12 patients, and a Woodman procedure in 1 patient. Twenty-five of the 30 patients (83%) were decannulated. Decannulation was more likely after a laryngofissure (84%) than after a laser arytenoidectomy (56%). The probability of decannulation was related to the presence of concomitant conditions and the need for other airway procedures. While breathiness, hoarseness, and pitch change were common, all patients had an adequate voice postoperatively and demonstrated little change from the preoperative voice disturbance. Aspiration was a rare complication. After an adequate period of observation for spontaneous resolution, arytenoidectomy via external laryngofissure is recommended to aid in the decannulation of children with bilateral true vocal cord paralysis.

The structural basis of the inhibition of human alpha-mannosidases by azafuranose analogues of mannose

Eight pyrrolidine, five pyrrolizidine and one indolizidine analogue(s) of the known alpha-mannosidase inhibitor, the azafuranose, 1,4-dideoxy-1,4-imino-D-mannitol (DIM), have been tested for inhibition of the multiple forms of alpha-mannosidase in human liver in vitro. Substitution of the ring nitrogen markedly decreased or abolished inhibition, but loss of the C-6 hydroxy group, as in 6-deoxy-DIM and 6-deoxy-6-fluoro-DIM, enhanced inhibition, particularly of the lysosomal alpha-mannosidase. Addition of the anomeric substituent-CH2OH decreased inhibition. To be a potent inhibitor of the lysosomal, Golgi II and neutral alpha-mannosidases, a polyhydroxylated pyrrolidine must have the same substituents and chirality as mannofuranose at C-2, C-3, C-4 and C-5. These four chiral centres can also be part of a polyhydroxylated indolizidine, e.g. swainsonine, but not of a pyrrolizidine, e.g. cyclized DIM, ring-contracted swainsonine or 1,7-diepi-australine. DIM did not inhibit lysosomal alpha-mannosidase intracellularly, but both 6-deoxy-DIM and 6-deoxy-6-fluoro-DIM caused accumulation of partially catabolized glycans in normal human fibroblasts. Analysis of these induced storage products by h.p.l.c. showed that both compounds also inhibited Golgi alpha-mannosidase II and that 6-deoxy-6-fluoro-DIM was also a good inhibitor of the endoplasmic reticulum alpha-mannosidase and specific lysosomal alpha (1-6)-mannosidase. None of the mannofuranose analogues appeared to inhibit Golgi alpha-mannosidase I.

Cyclosporin increases granulocyte/macrophage colony-stimulating factor (GM-CSF) activity and gene expression in murine keratinocytes

Keratinocytes produce multiple cytokines in response to a variety of stimuli. The release of interleukin 1 (IL-1) from keratinocytes may be significant in initiation of cutaneous inflammation, and the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) is thought to be important in the regulation of antigen-presenting function by epidermal Langerhans cells. Because cyclosporin inhibits interleukin 2 release from T cells, it has been suggested that cyclosporin may function as an anti-inflammatory agent within the epidermis through inhibition of keratinocyte cytokine release. This investigation examined the direct effect of cyclosporin on the production of GM-CSF by murine keratinocytes and the keratinocyte cell line PAM 212. GM-CSF bioactivity increased in cell supernatants from keratinocytes exposed in vitro to 1 microgram/ml cyclosporin for up to 24 h. GM-CSF and IL-1 mRNA levels in keratinocytes cultured under similar conditions or in the presence of lipopolysaccharide also increased. The lack of inhibition of GM-CSF expression following cyclosporin treatment is consistent with recent observations in T cells and is opposite to the effect of cyclosporin on interleukin 2.

Eversion endarterectomy of the cadaver donor renal artery: a method to increase the use of elderly donor kidney allografts

Eversion endarterectomy was used to treat severe arteriosclerosis of the renal artery in 34 cadaver kidneys from elderly donors that have been considered unsuitable by other transplant centers. All kidneys were transplanted after biopsy confirmed normal histology. Graft survival and mean serum creatinine level at 4 years were 76.4% and 2.3 mg./dl., respectively. Use of these kidneys increased the number of cadaver kidney transplants at our center by 18%.

Ti:LiNbO(3) polarization splitters using an asymmetric branching waveguide

Polarization splitters that use an asymmetric branching waveguide and can be fabricated along the Z axis as well as the X axis of LiNbO(3) are proposed and demonstrated. In these devices, two polarization states are converted to two different spatial modes, and these modes are split by the asymmetric branching waveguide. The extinction ratios of the two polarization splitters are shown to be less than -12 dB.