Studies on the initiation and elongation reactions in the simian virus 40 DNA replication system.

The synthesis of oligoribonucleotides by DNA primase in the presence of duplex DNA containing the simian virus 40 (SV40) origin of replication was examined. Small RNA chains (10-15 nucleotides) were synthesized in the presence of the four common ribonucleoside triphosphates, SV40 large tumor antigen (T antigen), the human DNA polymerase alpha (pol alpha)-DNA primase complex, the human single-stranded DNA-binding protein (HSSB), and topoisomerase I isolated from HeLa cells. The DNA primase-catalyzed reaction showed an absolute requirement for T antigen, HSSB, and pol alpha.

Posterior horizontal and vertical tightening to treat combined punctal ectropion with medial canthal tendon laxity.

The classical operations to treat either medial canthal tendon laxity or punctal aversion occurring alone possess drawbacks if they are used to treat these conditions when they occur simultaneously. A simplified procedure is described whereby tissue is removed via a posterior eyelid approach so that the eyelid may be tightened both horizontally and vertically, thus inverting the punctum and fixating it in the lacrimal lake. This procedure is quite easy to perform and can be done under local anesthesia in the office.

Orbital compartment syndrome. Direct measurement of orbital tissue pressure: 1. Technique.

Many disorders of the orbit produce an increase in intraorbital pressure, which may result in the development of an orbital compartment syndrome and visual loss. Traditionally, orbital tension is assessed clinically by indirect means based on retrodisplacement of the globe. The authors describe their experience with the "slit-catheter" technique for direct tissue pressure measurement as applied to the orbit.

First T cell receptor alpha gene rearrangements during T cell ontogeny skew to the 5' region of the J alpha locus.

Fetal, neonatal, and early postnatal thymi were assessed for TCR J alpha gene rearrangements. Gene probes spanning the distance from 5' to 3' regions of the J alpha locus were used to determine the approximate location of gene rearrangements within hybridomas representing each of the early thymocyte populations. The predominant location of rearrangements was within the 5' region of the J alpha locus.

The management of chalazion: a survey of Ontario ophthalmologists.

Owing to the variability and lack of standardization of chalazion management, a survey of Ontario ophthalmologists was undertaken. The results highlight what ophthalmologists consider to be problems in chalazion management and suggest that a chalazion operation should be treated with the same respect given any other operation.

A spindle-cell myoepithelioma of the lacrimal gland.

A middle-aged woman developed unilateral, painless proptosis that increased slowly over 1 year. A clinical diagnosis of pleomorphic adenoma of the lacrimal gland was supported by computed tomographic scanning and the tumor was excised. On histological examination the tumor proved to be a benign, myxoid myoepithelioma of spindle-cell type.

Mechanism of elongation of primed DNA by DNA polymerase delta, proliferating cell nuclear antigen, and activator 1.

In the presence of a single-stranded-DNA-binding protein (SSB), the elongation of primed DNA templates by DNA polymerase delta (pol delta) is dependent on ATP and two protein factors, activator 1 (A1) and proliferating cell nuclear antigen (PCNA). We have examined the interaction of these proteins with (dA)4500.(dT)12-18 by measuring their ability to form stable complexes with this DNA.

Concomitant T-cell receptor alpha and delta gene rearrangements in individual T-cell precursors.

A debate has recently surfaced concerning the degree of precommitment attained by alpha beta and gamma delta T-cell precursors prior to T-cell receptor (TCR) gene rearrangement. It has been suggested that precursors may be precommitted to rearrange either alpha or delta genes, but not both, thus giving rise to alpha beta- and gamma delta-producing T cells, respectively. Alternatively, the precursors may be flexible with regard to potential TCR gene rearrangements.

Nonsurgical aesthetic alteration of the eyelids in pathological conditions.

This study examines the potential value of camouflage and corrective make-up techniques in treating certain pathological eyelid conditions associated with cosmetic imperfections to determine whether surgery might be avoided. As well, these same techniques have been found to enhance postoperative results. The conclusions support the use of camouflage make-up and suggest the value of the combined expertise of the oculoplastic surgeon and clinical cosmetician.

In situ adenocarcinoma ex pleomorphic adenoma of the lacrimal gland.

We report a unique case of in situ adenocarcinoma ex pleomorphic adenoma of the lacrimal gland. The patient is alive and disease-free 2 1/2 years after complete local excision of the tumour. The current clinicopathologic status of this unusual tumour is discussed in the context of the reported experience to date.

Occurrence of atrial fibrillation in patients with paroxysmal supraventricular tachycardia due to atrioventricular nodal reentry.

The occurrence of atrial fibrillation in patients with paroxysmal supraventricular tachycardia (PSVT) has been well documented when PSVT is secondary to atrioventricular reentry, but not when PSVT is secondary to atrioventricular nodal reentry (AVNRT). Seventeen patients with AVNRT were followed using transtelephonic electrocardiogram monitoring to document symptomatic tachycardias. The median length of telephone monitor surveillance was 357 days.

The role of human single-stranded DNA binding protein and its individual subunits in simian virus 40 DNA replication.

Human single-stranded DNA binding protein (human SSB) is a multisubunit protein containing polypeptides of 70, 34, and 11 kDa that is required for SV40 DNA replication in vitro. In this report we identify the functions of the SSB and its individual subunits in SV40 DNA replication. The 70 kDa subunit was found to bind to single-stranded DNA, whereas the other subunits did not.

The position of the eyebrow.

The position of the eyebrow, which varies from person to person, is an important factor determining the final result of blepharoplasty, ptosis, and other aesthetic surgery. We developed a new instrument for measuring the position of the eyebrow--a clear, curved, plastic face mask with inscribed distance gradations in millimeters and a sliding horizontal step to catch the superior orbital rim for measurement.

Nonrandom rearrangement of T cell receptor J alpha genes in bone marrow T cell differentiation cultures.

TCR J alpha genes span a distance of approximately 65 kb on mouse chromosome 14. Due to the existence of 50 to 100 discrete J genes, a potential for great diversity exists within the V-J-C alpha gene products and within the ultimate repertoire of alpha beta TCR. We have prepared hybridomas from an in vitro system that supports T cell differentiation among bone marrow cells.

Treatment of severe lower eyelid retraction with scleral and free skin grafts and bipedicle orbicularis flap.

Surgical repair of lamellar shortening must treat the anterior and posterior shortening, plus the scarring between Mueller's muscle, capsulopalpebral fascia, and periosteum. We describe a repair method in which a full-thickness, free skin graft is used to correct the anterior lamellar defect, and a homologous scleral graft is used to correct the posterior defect. Vascular support for the two free grafts is provided by a bipedicular orbicularis muscle flap.

Assemblage of the prespliceosome complex with separated fractions isolated from HeLa cells.

The first ATP-dependent complex formed in pre-mRNA splicing is the prespliceosome, a 30 S complex. This reaction was investigated using partially purified fractions isolated from nuclear extracts of HeLa cells. Previous studies (Furneaux, H.

Isolated blow-in fracture of the lateral orbit causing globe rupture.

A blow-in fracture is a less common consequence of orbital trauma. Fragments of orbital bone may increase the orbital pressure, causing direct or indirect damage to the globe. This paper describes a blow-in fracture where a bone fragment perforated the globe causing globe disorganization and necessitating enucleation.

The true canalicular angle: a mathematical model.

A mathematical formula that allows for the computation of the true angle between the upper and lower canaliculi using dacryocystograms is described. It was used to determine the true canalicular angle in 33 patients. The mean calculated angle at the 1.

Association of entropion with cataract surgery.

Ptosis may develop after cataract surgery because of a dehiscence of the levator aponeurosis. A series of patients undergoing entropion repair was examined in order to determine the mechanism of entropion and the correlation with cataract surgery. It is suggested that involutional senile entropion may develop related to cataract surgery, on the same basis as ptosis, due to disinsertion of the capsulopalpebral fascia.

Teflon tubes for stenting and bypassing the lacrimal drainage pathways.

I report my experience using a new tear duct tube made from medical grade Teflon (Dupont) both as a bypass tube in situations in which a Pyrex Jones tube (Gunther Weiss, Portland Oregon) traditionally would be used, as well as a stent through the lower canaliculus, or as a bypass tube placed either through the lower canaliculus or at the inner canthus in connection with canaliculus laceration repair. After relatively brief follow-up, these Teflon tubes appeared to be associated with fewer complications than the Jones tube and in certain instances to offer other advantages as well.