CHORIORETINITIS SCLOPETARIA AND ORBITAL EMPHYSEMA CAUSED BY A HIGH-VELOCITY LIQUID MISSILE

PURPOSE

To highlight a case of chorioretinitis sclopetaria, with concomitant macular hole formation and orbital emphysema, caused by a commercial-grade pressure washer.

METHODS

This is a retrospective case report.

RESULTS

A 19-year-old man presented to the emergency department with a left eye injury, incurred after being sprayed with a commercial-grade pressure washer. He endorsed ipsilateral blurred vision, pain, and linear floaters. Left eye visual acuity was 20/40. Dilated fundus examination showed inferior vitreous hemorrhage, retinal whitening, and preretinal, intraretinal, and subretinal hemorrhages, consistent with chorioretinitis sclopetaria. Optical coherence tomography revealed a full-thickness macular hole. Computed tomography scan of the orbits showed subcutaneous and postseptal orbital emphysema. Two months after injury, vitreous and retinal hemorrhages and macular hole resolved. Five months after injury, visual acuity improved to 20/20.

CONCLUSION

Chorioretinitis sclopetaria is defined as a full-thickness chorioretinal disruption resulting from a high-velocity projectile passing adjacent to or into the orbit without penetrating the globe. Chorioretinal deformation and ocular comorbidities are influenced by the velocity of the missile and its spatial relationship to the orbit. Although this pattern of injury is typically associated with indirect trauma to the globe by a BB or a bullet, this is the first report of chorioretinitis sclopetaria precipitated by a high-velocity liquid missile.

Outcomes of Patients With Thyroid Eye Disease Partially Treated With Teprotumumab

PURPOSE

In response to the coronavirus (COVID-19) pandemic, teprotumumab production was temporarily halted with resources diverted toward vaccine production. Many patients who initiated treatment with teprotumumab for thyroid eye disease were forced to deviate from the standard protocol. This study investigates the response of teprotumumab when patients receive fewer than the standard 8-dose regimen.

METHODS

This observational cross-sectional cohort study included patients from 15 institutions with active or minimal to no clinical activity thyroid eye disease treated with the standard teprotumumab infusion protocol. Patients were included if they had completed at least 1 teprotumumab infusion and had not yet completed all 8 planned infusions. Data were collected before teprotumumab initiation, within 3 weeks of last dose before interruption, and at the visit before teprotumumab reinitiation. The primary outcome measure was reduction in proptosis more than 2 mm. Secondary outcome measures included change in clinical activity score (CAS), extraocular motility restriction, margin reflex distance-1 (MRD1), and reported adverse events.

RESULTS

The study included 74 patients. Mean age was 57.8 years, and 77% were female. There were 62 active and 12 minimal to no clinical activity patients. Patients completed an average of 4.2 teprotumumab infusions before interruption. A significant mean reduction in proptosis (-2.9 mm in active and -2.8 mm in minimal to no clinical activity patients, P < 0.01) was noted and maintained during interruption. For active patients, a 3.4-point reduction in CAS ( P < 0.01) and reduction in ocular motility restriction ( P < 0.01) were maintained during interruption.

CONCLUSIONS

Patients partially treated with teprotumumab achieve significant reduction in proptosis, CAS, and extraocular muscle restriction and maintain these improvements through the period of interruption.

A Case of the Blues-Colored Pencil Orbitopathy in an 18-Month-Old Boy

Orbital penetrating injuries from pencils are rare. This report describes a case of penetrating orbital injury in a young child with a retained blue-colored pencil core foreign body, which led to rapid onset of orbital abscess requiring surgical drainage. Intraoperatively, orbital tissues were stained a bright-blue color. Histopathological study of specimen also highlighted bright blue aggregates of foreign material infiltrating the orbital tissues. Cultures grew Streptococcus mitis and Exophiala jeanselmei , which are rare causes of orbital abscess. Unique properties of retained colored pencil core as compared to graphite pencil core are herein discussed. Due to differences in composition, colored pencil core foreign bodies may require more timely surgical intervention compared to noncolored graphite pencil core.

Development of Herpes Zoster Ophthalmicus in an Immunocompetent Pediatric Patient Following Facial Trauma

Herpes zoster ophthalmicus (HZO) is a neuro-oculo-dermic infection caused by reactivation of latent varicella zoster virus in the dorsal root ganglia of the ophthalmic division of the trigeminal nerve. Although a rare diagnosis in an otherwise healthy, vaccinated pediatric patient, this entity may occur with increasing frequency among those with preceding trauma, particularly in the month prior to presentation. Herein, we highlight a case of HZO in a vaccinated, immunocompetent adolescent in the setting of recent facial trauma.

Periorbital swelling and episcleritis may be a sign of cutaneous lupus erythematosus

It is important that physicians recognize persistent periorbital edema and conjunctival injection as possible disease manifestations of CLE, especially prior to cutaneous involvement. This may lead to more rapid diagnosis and treatment.

The Aesthetic Oculoplastic Surgery Video Teleconference Consult

BACKGROUND

Skype video telemedicine consults are gaining popularity to evaluate patients from distant locations. No study has analyzed the utility of this means of patient evaluation in a cosmetic oculoplastic patient population.

OBJECTIVES

The authors sought to provide an evidence-based analysis of the utility of Skype video consults in a cosmetic oculoplastic surgery patient population with regards to patient demographics, reasons for consult, and procedural conversion rate.

METHODS

A 1-year retrospective chart review (May 2016 to May 2017) of patients who underwent aesthetic oculoplastic Skype consults from 2 authors' practices was performed. The authors analyzed patient demographics, referral source, chief complaint, location of residence, length of consult, and conversion to face-to-face consultation and intervention.

RESULTS

Seventy-nine patients (60 women and 19 men) underwent Skype evaluations. Mean age was 49 years. Sixty-four consults (81%) lasted 15 minutes or less. Referral sources included the internet (67%), another physician (19%), self-referral (7.5%), referred by former patients (4%), and social media sites (2.5%). Consultations were obtained for revision (49%), or first-time (30%) eyelid/eyebrow surgery, cosmetic ptosis surgery (6%), laser skin procedures (5%), cosmetic orbital decompression (5%), and lower eyelid fat prolapse (5%). Twenty patients (25%) followed-up with in-person consultation. Sixteen of these patients (80%) had surgical (56%) or nonsurgical (44%) interventions.

CONCLUSIONS

Skype consults are an efficient, in-office modality to increase patient flow through the office, expand patient base, and generate income. In this report, 25% of Skype contacts followed-up with formal in-person consultations, of which 80% had surgical or nonsurgical interventions.

Non-coding rRNA-mediated preferential killing in cancer cells is enhanced by suppression of autophagy in non-transformed counterpart

Interest to anticancer agents targeting rRNA biogenesis is growing. Cis-non-coding rRNAs, alternative to primary rRNA, have been shown to regulate rRNA biogenesis. We have recently detected bidirectional non-coding rRNAs that carry ribozyme-like properties. Anti-antisense oligonucleotides complementary to antisense non-coding rRNAs markedly stabilized the bidirectional transcripts and induced cell death in mouse lung cells. Here, we demonstrated that the same oligonucleotide killed mouse lung-cancer cells preferentially, compared with non-cancer sister lines, suggesting its potential utility for cancer treatment. A human version of anti-antisense oligonucleotide, complementary to an rDNA intergenic site, mediated apoptosis primarily in cancer cells. Autophagic activation was largely undifferentiable between the anti-antisense and other oligonucleotides and accounted for the undesired cytotoxicity in non-cancer cells. Co-treatment with chloroquine, an autophagy inhibitor, reduced cytotoxicity in the non-cancer cells, but retained the anti-antisense-mediated killings in cancer cells. Furthermore, the anti-antisense oligonucleotide stabilized bidirectional non-coding rRNAs predominantly in human cancer cells and perturbed rRNA biogenesis. Contributions of non-coding rRNAs to cell death were proven by transfection of in –vitro-synthesized transcripts. Taken together, cancer/non-cancer cells respond differently to stabilization of non-coding rRNAs, and such differential responses provide a window of opportunity to enhance anticancer efficacy.

Geosmin and 2-methylisoborneol from cyanobacteria in three water supply systems

Three Oscillatoria strains and one Anabaena species were isolated from three different water supply systems in California that experienced earthy-musty taste and odor problems in their drinking water. Unialgal cultures, free of actinomycetes, were purged using the Grob closed-loop stripping analysis method, and the resulting methylene chloride extracts were analyzed on a gas chromatograph/mass spectrometer. Geosmin was produced by Oscillatoria simplicissima and Anabaena scheremetievi, and 2-methylisoborneol was produced by O. curviceps and O. tenuis. These compounds are the two major causes of earthy-musty tastes and odors in water. In three instances, the major odorant found in culture was previously identified in the water or sediment sample from which the respective organism was isolated. O. curviceps was implicated in a taste and odor episode involving 2-methylisoborneol in a major reservoir. Geosmin and 2-methylisoborneol were easily detected with culture samples of only 4 to 25 ml.

Abstract 4085: Bidirectional noncoding RNAs mediate rRNA processing and cell death in human lung adenocarcinoma cells

Increase in ribosome biogenesis is a characteristic of proliferating cells and may be causative in tumorigenesis. Significant increases in basal levels of several primary precursor transcripts during ribosomal RNA (rRNA) processing and of a cis antisense noncoding rRNA (AS-ncrRNA) near the main transcription start site were detected in human lung adenocarcinoma cells (H441 and A549) compared with non-transformed peripheral lung epithelial cells (HPL). A cis sense noncoding rRNA (S-ncrRNA) was also discovered but its levels showed cell-specific changes. It was hypothesized that a high level of the AS-ncrRNA is required to maintain the tumor phenotype. The functions of the AS-ncrRNA and S-ncrRNA were assessed using complementary oligonucleotides, termed −86S and −84AS (negative numbers correspond to the target locations in reference to the primary transcription start site) and intended for inhibiting the above targets, respectively. The levels of precursor rRNAs and both ncrRNAs in cells transfected with the −86S and −84AS oligonucleotides were measured using reverse transcription and quantitative polymerase chain reaction. Cell phenotypes and apoptotic cell death were also examined. A two-hit treatment with −86S 24 hrs apart induced cell detachment predominantly in H441 and A549 cancer cells. Detached cancer cells showed several hundred- to a thousand-fold upregulation of S-ncrRNA over the vehicle-treated controls while the S-nrcRNA in rare floating HPL cells was only increased by about 20 fold. Precursor rRNAs and AS-ncrRNA were also upregulated but to a lesser extent after −86S treatment in both adherent and detached cells. For the −84AS treatment, detached cells were fewer than after the −86S treatment; however those few floating cancer cells also exhibited several hundred-fold increase of the S-ncrRNA. Although the mechanism of upregulation is unclear, the S-ncrRNA may possibly act as a cell death regulator. Flow cytometric assays to detect fragmented DNA in cells after 24-hr and 48-hr treatments showed an apparent increase in apoptosis (2- to 4-fold) for the −86S treatment compared to −84AS and scrambled control. Further morphological analysis by transmission electron microscopy identified large and abundant autophagosomes and vacuoles preferentially in cancer cells, suggesting another possible cell death mechanism mediated by the oligonucleotide targeting AS-ncrRNA. In sum, rRNA processing and cis bidirectional noncoding rRNAs may form an interconnected network to maintain tumor phenotype. Interruption of this network by oligonucleotides targeting AS-ncrRNA activates massive elevation of the S-ncRNA level and sensitizes cancer cells preferentially for apoptotic and autophagic cell death. Targeting of AS-ncrRNA could have potential for human lung cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4085.

An intergenic non-coding rRNA correlated with expression of the rRNA and frequency of an rRNA single nucleotide polymorphism in lung cancer cells

Background

Ribosomal RNA (rRNA) is a central regulator of cell growth and may control cancer development. A cis noncoding rRNA (nc-rRNA) upstream from the 45S rRNA transcription start site has recently been implicated in control of rRNA transcription in mouse fibroblasts. We investigated whether a similar nc-rRNA might be expressed in human cancer epithelial cells, and related to any genomic characteristics.

Methodology/Principal Findings

Using quantitative rRNA measurement, we demonstrated that a nc-rRNA is transcribed in human lung epithelial and lung cancer cells, starting from approximately −1000 nucleotides upstream of the rRNA transcription start site (+1) and extending at least to +203. This nc-rRNA was significantly more abundant in the majority of lung cancer cell lines, relative to a nontransformed lung epithelial cell line. Its abundance correlated negatively with total 45S rRNA in 12 of 13 cell lines (P = 0.014). During sequence analysis from −388 to +306, we observed diverse, frequent intercopy single nucleotide polymorphisms (SNPs) in rRNA, with a frequency greater than predicted by chance at 12 sites. A SNP at +139 (U/C) in the 5′ leader sequence varied among the cell lines and correlated negatively with level of the nc-rRNA (P = 0.014). Modelling of the secondary structure of the rRNA 5′-leader sequence indicated a small increase in structural stability due to the +139 U/C SNP and a minor shift in local configuration occurrences.

Conclusions/Significance

The results demonstrate occurrence of a sense nc-rRNA in human lung epithelial and cancer cells, and imply a role in regulation of the rRNA gene, which may be affected by a +139 SNP in the 5′ leader sequence of the primary rRNA transcript.

Metal release from simulated fixed orthodontic appliances

Most orthodontic appliances and archwires are stainless steel or nickel-titanium (NiTi) alloys that can release metal ions, with saliva as the medium. To measure metal released from the fixed orthodontic appliances currently in use, we fabricated simulated fixed orthodontic appliances that corresponded to half of the maxillary arch and soaked them in 50 mL of artificial saliva (pH 6.75 +/- 0.15, 37 degrees C) for 3 months. We used brackets, tubes, and bands made by Tomy (Tokyo, Japan). Four groups were established according to the appliance manufacturer and the type of metal in the .016 x .022-in archwires. Groups A and B were stainless steel archwires from Ormco (Glendora, Calif) and Dentaurum (Ispringen, Germany), respectively, and groups C and D were both NiTi archwires with Ormco's copper NiTi and Tomy's Bioforce sentalloy, respectively. Stainless steel archwires were heat treated in an electric furnace at 500 degrees C for 1 minute and quenched in water. We measured the amount of metal released from each group by immersion time. Our conclusions were as follows: (1) there was no increase in the amount of chromium released after 4 weeks in group A, 2 weeks in group B, 3 weeks in group C, and 8 weeks in group D; (2) there was no increase in the amount of nickel released after 2 weeks in group A, 3 days in group B, 7 days in group C, and 3 weeks in group D; and (3) there was no increase in the amount of iron released after 2 weeks in group A, 3 days in group B, and 1 day in groups C and D. In our 3-month-long investigation, we saw a decrease in metal released as immersion time increased.

Hepatic resection for bilobar multicentric hepatocellular carcinoma: is it justified?

BACKGROUND

Hepatic resection for multiple hepatocellular carcinomas (HCCs) involving both lobes of the liver is rarely recommended because of high operative risks and low radicality. Thus the justification of hepatic resection for bilobar multicentric HCC remains undefined.

METHODS

Two hundred eleven patients with HCC, who underwent curative hepatic resection, were studied retrospectively. The patients were divided into two groups. Group A consisted of 39 patients with bilobar (both sides of Cantlie's line) multicentric HCCs. Group B consisted of 172 patients with HCC with solitary or unilobar lesions. The backgrounds and resectional results of patients in groups A and B were compared.

RESULTS

Patients in group A usually required multiple separate liver resections and a longer operative time. However, the operative blood loss, amount of blood transfused, and operative morbidity and mortality rates were not significantly different. Patients in group A showed higher incidences of associated satellite nodules, microscopic vascular invasion, and a lack of capsules. The 6-year disease-free and actuarial survival rates of patients in groups A and B were 30.5% and 41.8% (p = 0.17) and 42.9% and 51.4% (p = 0.12), respectively. For patients in group A the presence of satellite nodules in any resected tumor was the only independent unfavorable feature that influenced the actuarial survival rate after multivariate analysis.

CONCLUSIONS

Liver resection is justified for bilobar multicentric HCCs in selected patients, if the tumors can be totally resected. Postoperative adjuvant therapies should be considered when satellite nodules are present in any resected tumor.

Hydrosonography in the evaluation of colorectal polyps

Prewarmed saline enemas and transabdominal ultrasound (hydrosonography) were used to evaluate 17 consecutive children with rectal bleeding before colonoscopy. Twelve patients with polyps were identified (10 by ultrasound, 10 by endoscopy): these included multiple hyperplastic polyps (1), multiple polyps (1), solitary polyps (9), and pseudopolyps (1). Ultrasound identified 11 polyps in 10 patients, missing two patients with small polyps less than 0.5 cm in diameter. The polyps were hyperechoic ovoid masses fixed to the colonic wall, with a stalk (7), submucosal infolding (5), and intraluminal floating (5). There was one false positive. Colonoscopy was refused by one patient and failed to reach beyond the distal sigmoid in another following previous surgery for malrotation. Colonoscopy was superior in identifying finer mucosal detail (colitis, ulcers, proctitis, anal fissure) and in detecting smaller polyps (sessile polyps, hyperplastic polyps). Hydrosonography of the colon is a simple, relatively non-invasive procedure that provides an alternative, radiation-free examination of the whole colon before colonoscopy. It is complementary to colonoscopy in the management of rectal bleeding in children.

Definitive surgical treatment for cholelithiasis in selected patients with liver cirrhosis

To determine whether definitive surgery such as cholecysectomy or extraction of bile duct stones is appropriate in cirrhotic patients the results of definitive surgery have been reviewed retrospectively in a group of 112 cirrhotic patients with cholelithiasis. Eighty-seven of these patients underwent definitive surgery for gallstones and the remaining 25 were treated conservatively. Child's criteria were applied to each patient. Patients with Child's grade A disease had fewer emergency procedures, operative blood loss and transfusion were less and they had a shorter hospital stay compared with patients with grades B and C. There were 4 deaths after definitive surgery for emergency conditions and these were all in Child's grade C. Of the 83 survivors after definitive procedures 78 patients (93.9%) were still alive 52.8 months later without any biliary tract symptoms. Of the 25 patients undergoing conservative treatment 2 were Child's B and 23 were Child's C grade. We suggest that definitive surgery can be carried out safely, in Child's A and B cirrhotic patients, either electively or as an emergency. However, a more conservative approach is advisable in Child C patients with acute conditions and definitive surgery is recommended as an elective procedure after the liver function has improved.

Preliminary results of hepatic resection for centrally located large hepatocellular carcinoma

Resection of large hepatocellular carcinoma (HCC) located in the central portion of the liver remains a surgical challenge. Over a 2 year period, from July 1989, 19 HCC patients whose main tumour (mean diameter 11.3 cm, range 6-19 cm) was located in the central part of the liver (defined as Couinaud's segments IV, V, VIII) had liver resections. Liver cirrhosis was found in 14 patients (73.7%). Extended major hepatectomy could be performed in only three patients. The operative morbidity and mortality were 26.3% and 0%, respectively. The resection margin in 14 patients was less than 1 cm. At the time this paper was written 11 patients were alive and disease free, five patients survived longer than 30 months. The 1 year disease free rate and survival rate were 73.7% and 84.2%, respectively. The preliminary results reveal that with careful preservation of non-tumourous liver, resection of centrally located large HCC is still advocated even in a cirrhotic liver, and that the resection margin width should not be a major concern.

Definitive surgical treatment of cholelithiasis in selective patients with liver cirrhosis

A review of 132 cirrhotic patients with cholelithiasis was carried out. Of the 87 patients who underwent definitive surgical procedures for gallstones, patients of Child's A grade had less operative blood loss, blood transfusion and shorter hospital stay than those of B and C grades. No mortality in cirrhotic patients with Child's A and B grade was found in both emergency and elective surgery. Emergency operation in patients with Child's C grade resulted in more operative blood loss and requirement than elective surgery. Patients in this grade had also a higher morbidity rate and four deaths ensued. Of the 83 survivals after definitive procedures, 78 patients (93.9%) were still alive in the following 62.8 months without any biliary tract symptoms. Of patients who survived after cholecystolithotomy, 6 patients (33.3%) had recurrent stones in the same follow-up period. Therefore, we recommend that definitive biliary surgery be selectively carried out in cirrhotic patients in Child's A and B grade. However, a conservative approach is more suitable in Child's C patients in emergency conditions and definitive procedures should be considered when their liver function improves.

[Bleeding secondary duodenal diverticulum: a rare late complication following nephrolithotomy]

Secondary duodenal diverticula are due primarily to traction upon that section from some other cause such as ulcer, cholecystitis and so forth. It accounts for 1.6 to 20% of all duodenal diverticula. Numerous reports of gastrointestinal hemorrhage from duodenal diverticula have appeared in the literature. But massive UGI bleeding due to secondary duodenal diverticulum, caused by nephrolithotomy, was a rare late complication. Here we present a case of a 63-year-old male patient who underwent a right side nephrolithotomy 10 and 8 years previously, then developed massive UGI bleeding suddenly. Pre-operative UGI series and gastroscopy showed chronic duodenal ulcer and duodenal diverticulum at second section where much blood clot was noted. In time, a successful operation was performed. This complication of secondary duodenal diverticulum was rare, so consideration regarding management and surgical approach was discussed.

[Retrograde jejuno-jejunal intussusception. A rare complication following total gastric resection]

Jejunogastric intussusception is an infrequent complication following simple gastrojejunostomy or Billroth II anastomosis. Jejunojejunal intussusception through enteroenteric anastomosis following total gastrectomy, however, was reported in 2 cases. Here we present a case of a 59-year-old male patient with gastric ulcer who received a total gastrectomy with loop esophagojejunostomy and Braun's anastomosis 10 years previously, then developed retrograde jejunojejunal intussusception through Braun's anastomosis. The patient presented after a day of acute attacks of left upper quadrant pain with bilious vomiting. In-time, an operation was performed with successful results. This complication of retrograde jejunojejunal intussusception has never been reported. Clinical history, diagnosis, and treatment are discussed.

[Case reports of orthodontic treatment related to facial patterns]

This present paper describes 3 clinical cases which were treated according to facial patterns. First, facial pattern of each patient was classified by Ricketts's analysis and then, treatment objects and mechanics were determinded. Brachyfacial patterns are showed a resistant to mandibular rotation during treatment can accept a more prutrusion denture and primary treatment by nonextraction, whereas dolichofacial patterns were tended to open during treatment require a more retracted denture in order to assure post-treatment stability. Brachyfacial pattern would better treat to use extrusive force system, whereas dolichofacial pattern treat to use intrusive force system with head gear and intermaxillary elastics.

[Case reports and discussion on anterior open bite]

Anterior openbites cause impaired masticatory, malfunction of tongue, speech defects, disuse atrophy of teeth and periodontal tissue, esthetic problem. It is corrected by some available orthodontic methods according to its etiologic factors and growth stage. Removable appliances with tongue crib, spring loaded occlusal bite block, M.E.A.W. with rubber elastics, vertical chin cap and high pull head gear are selected for its correction. Extraction is considered for preventing wedging effect and Adenoidectomy is performed as adenoid cause mouth breathing. In the case of treatment of anterior openbites, combined therapy acquire better results than single treatment method. Removal of etiologic factors and accurate diagnosis is the best way of prevention of its recurrence.

Isolation of ketoses or nonreducing sugars from a sugar mixture containing aldoses by aniline treatment

A method for the isolation of ketoses and nonreducing sugars from sugar mixtures by the addition of aniline, in the presence of acetic acid as a catalyst, is described. The aldoses react readily to form aniline derivatives, which are then removed using standard procedures: extraction with organic solvents, and treatment with activated charcoal and with a cation-exchange resin. The ketoses and nonreducing sugars are retained in aqueous solution.

Characterization of angiotensin II binding sites on neuroblastoma X glioma hybrid cells

Mouse neuroblastoma X rat glioma hybrid cells, NG108-15, have recently been shown to contain immunoreactive angiotensin II (AII). In the present study, we have examined this hybrid cell line for the presence of specific AII binding sites using [125I] AII. Specific AII binding was saturable and reversible. Scatchard analysis revealed a linear plot with an affinity constant (Kd) of 0.323 nM and a binding capacity (Bmax) of 7.13 fmol/mg protein. Kinetic studies demonstrated an association rate constant (K+1) of 3.55 X 10(6) M(-1) sec-1 and a dissociation rate constant (K-1) of 4.18 X 10(-4) sec-1. Displacement curves, using concentrations of 10(-11) M to 10(-4) M of unlabeled AII, revealed high and low affinity components of the AII binding site with IC50's of 0.46 nM and 1.75 microM respectively. The AII antagonist, saralasin, had approximately equal potency with unlabeled AII at the high affinity site. Furthermore, structurally related and unrelated peptides had no significant inhibitory effect on AII binding. This study demonstrates that specific AII binding sites are present on NG108-15 cells, and that these binding sites are similar in kinetic character to the AII receptor that has been previously identified in membranes from mammalian brain. It is concluded that the NG108-15 hybrid cells may provide a useful continuous cell line model for investigating both the biochemical and molecular properties of the AII binding site.

LINKAGE OF MUTATIONS AFFECTING MINUS FLAGELLAR MEMBRANE AGGLUTINABILITY TO THE mt - MATING-TYPE LOCUS OF CHLAMYDOMONAS

Two independently isolated mutant strains, imp-10 and imp-12, were obtained by UV irradiation of wild-type mating-type minus (wt-). Each fails to agglutinate sexually with gametes of either mating type, but mating and zygote formation can be elicited by agglutinating either strain to wt+ gametes by means of anti-flagellar antiserum. Tetrad analysis of the resultant zygotes shows that both imp-10 and imp-12 are very closely linked to mt  -, with no recombinants observed. Diploid strains constructed between imp-10 or imp-12 and wt+ gametes are wt-, that is, they agglutinate and fuse like normal minus cells. Tetrad analysis of triploids from imp-10 diploid x wt+ haploid crosses shows that only imp-10 and wt+ products are recovered. A model is proposed to account for these results.