Selective degradation of ubiquitinated Sic1 by purified 26S proteasome yields active S phase cyclin-Cdk

Selective degradation of single subunits of multimeric complexes by the ubiquitin pathway underlies multiple regulatory switches, including those involving cyclins and Cdk inhibitors. The machinery that segregates ubiquitinated proteins from unmodified partners prior to degradation remains undefined. We report that ubiquitinated Sic1 (Ub-Sic1) embedded within inactive S phase cyclin-Cdk (S-Cdk) complexes was rapidly degraded by purified 26S proteasomes, yielding active S-Cdk. Mutant proteasomes that failed to degrade Ub-Sic1 activated S-Cdk only partially in an ATP-dependent manner. Whereas Ub-Sic1 was degraded within approximately 2 min, spontaneous dissociation of Ub-Sic1 from S-Cdk was approximately 200-fold slower. We propose that the 26S proteasome has the intrinsic capability to extract, unfold, and degrade ubiquitinated proteins while releasing bound partners untouched. Activation of S-Cdk reported herein represents a complete reconstitution of the regulatory switch underlying the G1/S transition in budding yeast.

Moral, ethical and professional issues in prescribing emergency contraception

Hugh McDonald is an emergency nurse practitioner with the authority to manage a defined group of patients who present to A&E with a specific range of complaints and injuries. Investigation, diagnosis and treatment are carried out independently and include documentation and prescription of specific drugs.

Assessment of ocular trauma associated with head and neck injuries

We reviewed the real and potential ocular problems in all head and neck injuries at a tertiary care and regional trauma center from April of 1994 to March of 1995. Through a retrospective study, 127 charts were reviewed, specifically looking at the mechanism of injury, types of injury, whether there was any ocular trauma noted in the chart, and whether there was a consultation to the ophthalmology department. Forty-one of these patients were seen by an ophthalmologist as the initial consultant for ocular and orbital injuries recognized by the emergency staff. In the 86 remaining patients, signs of potential ocular injury were recorded in the chart in 62 (72%) of these patients, yet an ophthalmology consultation was requested for only 23 of them (37%). This survey reveals the lack of awareness in a regional trauma center of certain ocular and periocular signs that may be indicative of more serious ocular injuries. It is the purpose of this article to highlight these concerns to the various health professionals involved with head and neck trauma patients in the hope that the patients will, in the end, benefit from a more thorough and complete assessment of the potential ocular and periocular injuries.

Structural analysis of the 5' region of mouse and human Huntington disease genes reveals conservation of putative promoter region and di- and trinucleotide polymorphisms

We have previously cloned and characterized the murine homologue of the Huntington disease (HD) gene and shown that it maps to mouse chromosome 5 within a region of conserved synteny with human chromosome 4p16.3. Here we present a detailed comparison of the sequence of the putative promoter and the organization of the 5' genomic region of the murine (Hdh) and human HD genes encompassing the first five exons. We show that in this region these two genes share identical exon boundaries, but have different-size introns. Two dinucleotide (CT) and one trinucleotide intronic polymorphism in Hdh and an intronic CA polymorphism in the HD gene were identified. Comparison of 940-bp sequence 5' to the putative translation start site reveals a highly conserved region (78.8% nucleotide identity) between Hdh and the HD gene from nucleotide -56 to -206 (of Hdh). Neither Hdh nor the HD gene have typical TATA or CCAAT elements, but both show one putative AP2 binding site and numerous potential Sp1 binding sites. The high sequence identity between Hdh and the HD gene for approximately 200 bp 5' to the putative translation start site indicates that these sequences may play a role in regulating expression of the Huntington disease gene.

Genomic organization of the human alpha-adducin gene and its alternately spliced isoforms

The cDNA for the human alpha-adducin gene has been cloned, and different alternately spliced forms have been identified. We report the complete genomic organization of the human alpha-adducin gene and these alternately spliced forms. The human alpha-adducin gene, spanning approximately 85 kb, consists of 16 exons ranging in size from 34 to 1892 bp. One of the spliced forms of the human alpha-adducin gene results from alternate use of the 5' splice donor site for exon 10, while another results in a truncated protein following insertion of 34 bp comprising exon 15, followed by a premature stop codon. This alternate spliced form of alpha-adducin is predicted to result in an altered carboxyl terminus that would eliminate a protein kinase and calmodulin binding site. Seven nucleotide substitutions and 4 insertion/deletions were also identified. The 5' region of the human alpha-adducin gene contains one Sp1 site, two AP2 sites, and two CAAT boxes. No TATA box was apparent, consistent with features of a housekeeping gene. We have mapped another cDNA within the first intron of the human alpha-adducin gene, suggesting overlapping genes in this 4p16.3 genomic region.

Irradiated homologous aorta in eyelid reconstruction. Part II. Human data

Reconstruction of posterior lamellar eyelid defects requires a tissue substitute that is either identical to the tissue lost (i.e., surrounding or nearby tarsus) or donor tissue that serves the same supportive role. With extensive lid defects, at times an alternative tissue to tarsus may be required. Irradiated homologous aorta is available as a posterior lamellar substitute. It provides a structural framework for the surrounding lid tissues to grow on and is incorporated into the normal eyelid anatomy. It is available to the reconstructive ophthalmic surgeons as an alternative donor tissue in the presence of extensive lid defects.

Murine alpha-L-iduronidase: cDNA isolation and expression

As an initial step toward the generation of a murine model for mucopolysaccharidosis type I, we have identified and characterized a full-length murine alpha-L-iduronidase cDNA. Expression of the murine cDNA in COS-1 cells results in the production of alpha-L-iduronidase enzyme activity at a level 20-fold higher than that of the endogenous gene. The murine cDNA shows strong homology with the coding region of both the human and the canine homologs with 78 and 75% nucleotide sequence identity, respectively. In contrast to the coding region, significant diversity of sequence exists for the 5' and 3' untranslated regions between the murine and both the human and the canine sequence. The 3' UTR of the murine transcript is 1193 bp in length, as compared to the human (100 bp) and canine (139 bp), and contains a CA dinucleotide repeat not seen in either the human or the canine genes. A portion of the murine iduronidase coding sequence overlaps with sequence reported for the 3' UTR of the murine SAT-1 cDNA. The sequence overlap involves the proposed exon II of murine iduronidase and covers 141 bp of sequence with the transcripts generated in opposite orientation. We report here the characterization of murine alpha-L-iduronidase cDNA and its relationship to SAT-1.

Irradiated homologous aorta in eyelid reconstruction. Part 1: Technique and animal research

Reconstruction of full thickness eyelid defects requires the correction of posterior lamella (tarsus, conjunctiva) and anterior lamella (skin, muscle). Various tarsal substitutes--conchal and nasal cartilage, banked sclera, hard palate, irradiated homologous tarsal plates, periosteum, temporalis fascia, and composite grafts from the opposite eyelid--have been used for posterior lamellar replacement over the years. Eyelid-sharing procedures and full thickness flaps have also been described. At times, because of extensive tissue loss, the eyelid reconstruction can be particularly challenging because of the shortage of tissue. We describe a new posterior lamellar technique using irradiated homologous aorta. The experimental surgical procedure in rabbits, the clinical response, and the histological fate of the donor aorta are described in Part 1 followed by our experience with four patients in Part 2.

Failed dacryocystorhinostomy: the sump syndrome

A dacryocystorhinostomy may fail due to a problem along the canaliculus, at the ostomy site of nasolacrimal sac to nose, due to an intranasal problem or related to the stent. The "sump syndrome" occurs when a residual nasolacrimal sac forms, collects fluids, and leads to tearing. This entity, although uncommon, has a characteristic clinical history and radiologic appearance.

An Alu element retroposition in two families with Huntington disease defines a new active Alu subfamily

Alu repetitive elements represent the most common short interspersed elements (SINEs) found in primates, with an estimated 500,000 members in the haploid human genome. Considerable evidence has accumulated that these elements have dispersed in the genome by active transcription followed by retroposition, and that this process is ongoing. Sequence variation between the individual elements has lead to the hierarchical classification of Alu repeats into families and subfamilies. Young subfamilies that are still being actively transposed are of considerable interest, and the identification of one such subfamily (designated 'PV') has lead to the hypothesis that the most recent retroposition events are due to a single master Alu source gene. In the course of our search for the gene causing Huntington disease, we have detected an Alu retroposition event in two families. Sequence analysis demonstrates that this Alu element is not a member of the PV subfamily, but is similar to 5 other Alu elements in the GenBank database. Together, these Alu elements, all of which contain a 7 base-pair internal duplication, define a distinct subfamily, designated as the Sb2 subfamily, providing evidence for a second actively retroposing Alu source gene. These data provide support for multiple source genes for Alu retroposition in the human genome.

A survey of exercise testing practice in Scottish hospitals

A 1989 survey (unpublished) of exercise testing practice in Scotland suggested that there were important differences in the practice of exercise testing between hospitals. A postal questionnaire was sent to 30 teaching and district general hospitals in 1991 and followed up by telephone questioning of consultants. The numbers of exercise tests performed had increased to 22,012 in 1990, and a greater proportion were performed in district general hospitals. General practitioners had very limited access to the service but hospital doctors of any grade had almost free access. Rationing of early post myocardial infarction testing led to attempts to define "high risk" post infarction patients and this included inappropriate patients in many hospitals. A variety of different protocols was used. Eighteen out of 30 hospitals surveyed discontinued beta blockers but only four hospitals took account of antianginal, antihypertensive or other medication, and all but one exercised patients while on digoxin. In the majority of hospitals decisions regarding drug therapy were taken by individual physicians. A variety of personnel reported tests, many without specialist training in cardiology. Even among consultants there was no concerns on the degree of ST depression which was significant. Exercise tests performed in different hospitals in Scotland are not comparable due to the wide variation in patient selection, test conditions, and interpretation of tests. This problem is likely to be exacerbated by the multiple personnel involved in all aspects of testing. It seems probable that there is a problem throughout the United Kingdom, and that there is a need for guidelines.

Identification of an Alu retrotransposition event in close proximity to a strong candidate gene for Huntington's disease

Huntington's disease (HD) is a late-onset autosomal dominant neuropsychiatric disorder presenting in mid-adult life with personality disturbance and involuntary movements, cognitive and affective disturbance, and inexorable progression to death. The underlying genetic defect has been mapped to chromosomal band 4p16.3 (refs 2, 3). Analysis of specific recombination events in some families with HD has further refined the location of the HD defect to a 2.2 megabase DNA interval. Using a direct complementary DNA selection strategy we have identified at least seven transcriptional units within the minimal region believed to contain the HD gene. Screening with one of the cDNA clones identified an Alu insertion in genomic DNA from two persons with HD which showed complete cosegregation with the disease in these families but was not found in 1,000 control chromosomes. Two genes including the previously identified alpha-adducin gene and another that encodes for a 12-kilobase transcript, map in close proximity to the Alu insertion site. The 12-kilobase transcript should be regarded as a strong candidate for the HD gene.

Orbital panniculitis as the initial manifestation of systemic lupus erythematosus

Inflammation of the fat in lupus erythematosus also known as lupus erythematosus profundus (panniculitis) is a rare clinical entity. As the presenting feature of lupus, it is even more unusual. In this report, we describe an elderly woman who presented with an orbital mass infiltrate as the initial manifestation of lupus that had the classical histological features of lupus panniculitis.

Microblepharon

We describe a child with microblepharon and corneal exposure secondary to lagophthalmos. Surgical reconstruction utilizing full-thickness skin grafts to all four lids corrected the lagophthalmos and relieved her symptoms.

Identification and characterization of a gene at D10S94 in the MEN2A region

We have identified a candidate for the gene responsible for multiple endocrine neoplasia type 2A (MEN 2A) at D10S94 in proximal 10q11.2. An evolutionarily conserved sequence from D10S94 was used as a probe to isolate cDNAs corresponding to a gene that we have termed mcs94-1. The gene spans 11 kb and has an unmethylated CpG island at its 5' end. The mcs94-1 transcript is approximately 2.4 kb in length and is widely expressed. It encodes a putative 415-amino-acid polypeptide that is similar in sequence to nucleolin, an abundant nucleolar protein. Mcs94-1 was examined as a candidate for MEN2A through nucleotide sequence analysis of mcs94-1 exons from an MEN 2A chromosome and its wildtype homologue from an MEN 2A patient. The major portion of the expressed mcs94-1 sequence was examined. No differences in sequence were found between the two alleles.

Comparison of pain, motion, and edema after modified radical mastectomy vs. local excision with axillary dissection and radiation

Recent data suggest that prognosis is similar for women with primary breast cancer whether they receive modified radical mastectomy (MRM) or local excision and axillary dissection with radiation (XRT). The effects of either of these treatments on arm mobility, pain, or edema have not been compared. To assess the impact of MRM or XRT on mobility, pain, or edema, we evaluated patients treated in a prospective randomized trial designed to assess prognosis following MRM or XRT. All were provided a standardized physical therapy program including arm mobilization, shoulder strengthening, prevention and treatment of upper extremity edema, and education about arm function. Patients were evaluated for chest wall pain, arm motion, muscle strength, and edema as determined by circumferential measurements at the wrist, forearm, and arm. Evaluations were performed preoperatively and at yearly anniversaries of their surgery. Women receiving XRT had more chest wall tenderness at 1 and 2 years after surgery than those receiving MRM (p2 less than 0.0001 and p2 = 0.0007 respectively). Those receiving MRM were slower to reach their preoperative range of motion (ROM) (p2 = 0.043). Incidence of muscle weakness was similar in both groups. The few patients with local recurrence of tumor had more upper extremity edema than those who did not recur (p2 = 0.085) at 1 year and (p2 = 0.02) at 2 years. In patients who did not develop local recurrence, those who had received XRT had greater but nonsignificant increases in upper extremity circumferential measures compared with those receiving MRM at any anniversary evaluation. Patients receiving MRM and XRT are likely to have some differences in functional outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of capsid protein cleavage on the processing of E2 and E1 glycoproteins of rubella virus

The structural polyprotein of rubella virus is cotranslationally processed by host cell signal peptidase. Oligonucleotide-directed mutagenesis was used to alter the cleavage site between capsid and E2 proteins and to examine the importance of this cleavage for the transport and processing of E2 and E1 glycoproteins. The in vitro and in vivo expression of the cleavage site mutant revealed that the E2 polypeptide can cross the endoplasmic reticulum membrane without the cleavage of its signal peptide, while the transport of E2 beyond the endoplasmic reticulum requires the cleavage of E2 from capsid. We have shown that capsid protein does not appear to undergo further proteolytic processing after it is cleaved from E2 by signal peptidase. Some of the requirements for the cleavage by signal peptidase between capsid and E2 were examined by the in vitro analysis of wild-type and mutant cDNAs.

Immediate postexcision mammography for occult noncalcified breast lesions

To evaluate completeness of surgical excision, we studied the use of film screen mammography done immediately after excision of occult noncalcified breast lesions in 11 patients. The postoperative mammograms were well tolerated, and allowed high quality films to be obtained. Complete excision was documented in ten patients, and one patient had small artifacts that resolved on follow-up studies. Roentgenograms of the surgical specimen from ten patients showed a discrete lesion in only three. Histologic analysis revealed malignancy in two patients and benign changes in nine. These findings indicate that mammography done immediately after excision of occult noncalcified lesions is more reliable than roentgenograms of the specimen and may be a useful method for confirming extent of excision. This method may also eliminate the present delay of four to six weeks before adequate postoperative follow-up films can be obtained to evaluate excision.

Effect of preoperative chemotherapy on mastectomy for locally advanced breast cancer

Mastectomy is frequently performed after intensive chemotherapy for locally advanced breast cancer. The effects of preoperative chemotherapy on the postoperative course and the timing of subsequent adjuvant therapy, however, have not been defined. We therefore reviewed the perioperative course of 54 patients undergoing mastectomy after combination (CAMFPT) chemotherapy for stage IIIA,B (IIIA - 25 pts; IIIB noninflammatory - 5 pts; IIIB inflammatory-24 patients) breast cancer. A median of 7 cycles (6 months) of chemotherapy was administered preoperatively. Mastectomy was performed a median of 20 days after last chemotherapy; white blood cell count (WBC) and platelet counts returned to normal limits preoperatively. Total mastectomy with or without axillary node dissection was performed in 53 patients, and a Halsted radical mastectomy in 1 patient. Negative margins on breast and/or axillary tissue were achieved in 47 patients (87.0%). Postoperative complications included skin flap necrosis in 8 patients (14.8%), seroma formation in 5 patients (9.3%), and wound infection in 1 patient (1.9%). Median operative blood loss (550 cc), hospital stay (8 days), and duration of wound catheter drainage (6 days) were comparable to published reports for modified radical mastectomy without preoperative chemotherapy. Systemic chemotherapy was resumed a median of 16 days after mastectomy, and radiotherapy started a median of 33 days after mastectomy. These findings indicate that intensive preoperative chemotherapy does not increase the hospital course or the postoperative complications of mastectomy for locally advanced breast cancer. In view of the current interest in treatment of stage I and II breast cancer with preoperative chemotherapy, this information may be useful in their management as well.