Histopathological and ultrasound biomicroscopy findings in a case of irreversible mydriasis after keratoplasty in keratoconus

This report describes the histopathological and ultrasound biomicroscopy findings of a 35-year-old woman with keratoconus who developed an irreversible mydriasis after keratoplasty.

Selenocysteine tRNA[Ser]Sec levels and selenium-dependent glutathione peroxidase activity in mouse embryonic stem cells heterozygous for a targeted mutation in the tRNA[Ser]Sec gene

To investigate the effect of a reduced level of selenocysteine (Sec) tRNA[Ser]Sec in selenoprotein biosynthesis, two mouse embryonic stem (ES) cell lines heterozygous for the corresponding gene were generated by homologous recombination of the host genome with targeting vectors encoding a deleted or a disrupted tRNA[Ser]Sec gene. The presence of a single functional gene in ES cells afforded us an opportunity to determine directly in the cell line the effect of reduced gene dosage on (1) the levels of the Sec tRNA[Ser]Sec population, (2) the distributions of the isoacceptors within the Sec tRNA population, and (3) selenoprotein biosynthesis. We therefore determined the amounts and distributions of the two major tRNA[Ser]Sec isoacceptors, designated mcm5U and mcm5Um, within the Sec tRNA population and determined the activity of the anti-oxidant, selenium-containing glutathione peroxidase (GPx) in the heterozygotes and in wild type cells grown in media with and without added selenium. The level of the Sec tRNA[Ser]Sec population in the heterozygotes was approximately 60% of that of wild type cells grown in media under normal conditions, while the ratio of the mcmU isoacceptor in wild type vs mutant cells was approximately 2:1 and of the mcmUm isoacceptor approximately 1:1. In the presence of media supplemented with selenium, the Sec tRNA[Ser]Sec population increased about 20% in wild type cells and virtually not all in heterozygous cells, and the level of the Sec tRNA[Ser]Sec population was, therefore, approximately 50% of that of wild type cells. GPx activity was indistinguishable among these cell lines in either selenium-supplemented or unsupplemented media, indicating that the resultant changes in tRNA[Ser]Sec levels did not have a measurable effect on GPx biosynthesis.

Effects of aspirin or basic amino acids on collagen cross-links and complications in NIDDM

OBJECTIVE

To determine if long-term therapy with aspirin or basic amino acids for subjects with NIDDM reduces the severity of clinical complications and/or reduces tissue levels of markers of glycooxidative damage.

RESEARCH DESIGN AND METHODS

Subjects with NIDDM were administered either aspirin (100 mg/day) or a combination of basic amino acids consisting of L-arginine (2 g/day) plus L-lysine (0.5 g/day) for 1 year. The study was double-blind and placebo-controlled. The presence and severity of retinopathy, nephropathy, and neuropathy were assessed in all subjects at 4-month intervals, as were serum blood glucose, glycohemoglobin levels, and presence of albuminuria. Collagen cross-linking and collagen glycation were measured in skin collagen obtained by biopsy at the beginning and the end of the study. Skin biopsies were also obtained from age-matched control subjects.

RESULTS

Skin samples obtained from NIDDM subjects at the beginning of the study had significantly increased levels of glucitolyllysine, pentosidine, and hydroxypyridinium, as compared with age-matched control subjects. Pentosidine levels were significantly correlated with severity of retinopathy and neuropathy, but not nephropathy. Subjects receiving aspirin, but not amino acids or placebo, had significantly decreased levels of skin pentosidine after 1 year of therapy.

CONCLUSIONS

It is concluded that 1) low-dose aspirin may reduce glycooxidative damage in people with NIDDM, and 2) treatment may need to continue for more than 1 year before clinical status improves.

Adrenal involvement in polycystic ovary syndrome

The etiology of hyperandrogenic chronic anovulation is heterogeneous and relatively unknown in the majority of cases. Affected individuals in this latter segment are considered to have polycystic ovary syndrome (PCOS) of which 50 to 60% exhibit androgen excess of adrenal origin. An understanding of normal adrenal function provides insight into the factors that contribute to adrenal androgen excess in PCOS. Since pituitary ACTH secretion promotes developmental growth and overall steroidogenic efficiency within the adrenal cortex, it is probable that these actions of ACTH along with the adrenal's unique centripetal circulation play a major role in the induction of adrenarche. This latter phenomenon is characterized by alterations in adrenocortical morphology and steroidogenic enzyme activities culminating in increases in adrenal androgens to normal circulating adult levels. Thus, it is not surprising that adrenal dynamic testing has revealed increased 17,20 lyase activity or adrenal androgen hyper-responsiveness to ACTH as the two abnormalities leading to adrenal androgen excess in PCOS. Whereas 17,20 lyase hyperactivity diagnosed by defined criteria in response to pharmacological ACTH may be an intrinsic genetic defect, increases in 17,20 lyase activity and adrenal androgen hyper-responsiveness to ACTH in response to physiological ACTH may be promoted by the functional elevation of estrogen of ovarian origin in PCOS. The latest in vitro data suggest the estrogen may elicit its effect on the adrenal cortex through a receptor mediated mechanism. Therefore, the currently available data indicate that adrenal androgen excess in PCOS is also heterogeneous in etiology.

Evaluation and management of heterotopic ossification in patients with spinal cord injury

Sixty-three patients with paralysis secondary to spinal cord injury (SCI) were screened for heterotopic ossification (HO) by bone scintigraphy 27 +/- 14 (mean +/- SD) days after SCI. There were four female and 59 male patients, 36 had paraplegia and 27 tetraplegia. The age of patients was 28 +/- 9 years. Bone scintigraphy was obtained with a 3-phase test using 99m-technetium labeled diphosphonate, and the positive third phase was used as a criterion for diagnosis of HO. Bone scintigraphy was negative for HO in 27 patients (14 tetraplegic and 13 paraplegic) and positive in 36 patients (13 tetraplegic and 23 paraplegic). The patients with positive HO were treated with etidronate, first with an intravenous dose of 300 mg/day for 3 days, and then with an oral dose of 20 mg/kg/day for 6 months. The follow-up of patients consisted of clinical and radiographic evaluations every 2-4 months. The extent of HO was classified radiographically. In the treated group of patients who completed the entire course of etidronate therapy one patient developed HO, the remaining 28 (97%) patients had no radiographic evidence of HO during the follow-up of 10.6 +/- 4.5 months after initiation of therapy. Our data indicate that: (a) early HO can be detected in the asymptomatic patients using bone scintigraphy on the average of 4 weeks (27 +/- 14 days) after SCI and (b) the therapy with etidronate might be effective in the prevention of HO in majority of patients when the treatment is initiated in an early stage of heterotopic bone formation.

Treatment of heterotopic ossification after spinal cord injury

A new protocol in management of heterotopic ossification (HO) was evaluated in 46 patients after spinal cord injury (SCI). A group of 24 paraplegic and 22 tetraplegic patients was involved in a prospective study. Diagnosis of HO was made by bone scintigraphy and radiographic evaluation. Patients were divided into two groups. Group I was made up of 33 patients with positive bone scintigraphy and negative evidence of HO and Group II was made up of 13 patients with positive bone scintigraphy and positive radiographic evidence of HO. Etidronate was started intravenously (300 mg/day) for three days followed by oral therapy for six months (20 mg/kg/day). Follow-up of patients was 15.7 +/- 8 months after SCI. In Group I, etidronate therapy prevented the development of HO in 79 percent of patients; in 21 percent of patients, a low degree of tissue ossification was found which was not clinically significant. In Group II, there was an inhibitory effect of etidronate on progression of soft tissue ossification in six patients. The remaining seven patients did not respond to therapy and showed an increased growth of HO. Our data indicate that etidronate may prevent HO in the majority of patients when administered at an early stage of HO development and in higher doses than are routinely recommended.

Alloreactive CD8+ T cells can recognize unusual, rare, and unique processed peptide/MHC complexes

The identity and abundance of self-peptide/MHC class I complexes that serve as ligands for alloreactive T cells remain largely unknown. Using the Kb-restricted, alloreactive T cells as a probe, the Ag precursor gene, adenosine phosphoribosyl transferase (APRT), was isolated by expression cloning. Its naturally processed product was identified as the SLVELTSL (SEL8) octapeptide. The SEL8 peptide shared five residues with the previously identified SVVEFSSL (JAL8) peptide that stimulated the same T cell, but lacked the critical phenylalanine/tyrosine residue at the primary p5 anchor position. Despite the absence of this key conserved anchor residue, SEL8 was bound tightly by Kb MHC and yet was expressed at less than 10 copies/cell. Mutations in the donor APRT gene in the APC caused a concomitant loss in the ability of APCs to stimulate T cells. The results confirm that the display of peptide/MHC complexes in cells exceeds the predictions based upon consensus motifs, and that CD8+ alloreactive and conventional Ag-specific T cells are indistinguishable in their ability to recognize unique and rare peptide/MHC class I complexes.

Alloreactive CD8+ T cells can recognize unusual, rare, and unique processed peptide/MHC complexes

The identity and abundance of self-peptide/MHC class I complexes that serve as ligands for alloreactive T cells remain largely unknown. Using the Kb-restricted, alloreactive T cells as a probe, the Ag precursor gene, adenosine phosphoribosyl transferase (APRT), was isolated by expression cloning. Its naturally processed product was identified as the SLVELTSL (SEL8) octapeptide. The SEL8 peptide shared five residues with the previously identified SVVEFSSL (JAL8) peptide that stimulated the same T cell, but lacked the critical phenylalanine/tyrosine residue at the primary p5 anchor position. Despite the absence of this key conserved anchor residue, SEL8 was bound tightly by Kb MHC and yet was expressed at less than 10 copies/cell. Mutations in the donor APRT gene in the APC caused a concomitant loss in the ability of APCs to stimulate T cells. The results confirm that the display of peptide/MHC complexes in cells exceeds the predictions based upon consensus motifs, and that CD8+ alloreactive and conventional Ag-specific T cells are indistinguishable in their ability to recognize unique and rare peptide/MHC class I complexes.

Evidence for heterogeneous etiologies of adrenal dysfunction in polycystic ovary syndrome

OBJECTIVE

To examine the hypothesis that, in polycystic ovary syndrome (PCOS), ovarian steroids induce adrenal enzyme dysfunction or adrenal androgen hyperresponsiveness to ACTH.

DESIGN

Prospective controlled clinical study.

SETTING

Reproductive endocrinology unit of an academic medical center.

PATIENTS

Twelve women with PCOS who had adrenal androgen excess were compared with five weight-matched ovulatory women. In half of the women with PCOS, prestudy screening was suggestive of mild 3 beta-hydroxysteroid dehydrogenase (HSD) deficiency.

INTERVENTIONS

Basal and adrenal dynamic blood sampling before and after GnRH agonist (GnRH-a) administration for 6 months.

MAIN OUTCOME MEASURES

Basal E2 and androgen levels as well as dexamethasone-suppressed, ACTH-stimulated 17 alpha-hydroxyprogesterone, 17 alpha-hydroxypregnenolone, and androgen levels before and after ovarian suppression.

RESULTS

Although none of the subjects with PCOS proved to have mild 3 beta-HSD deficiency, the majority of them (58%) met the criteria for 17,20 lyase hyperactivity before and after GnRH-a therapy. As a group, the remaining subjects with PCOS exhibited an elevated DHEAS response to ACTH before GnRH-a treatment, which may have normalized after GnRH-a treatment.

CONCLUSION

Adrenal androgen excess in PCOS may be heterogeneous in etiology, whereas 17,20 lyase hyperactivity appears to be an intrinsic adrenal disorder, adrenal androgen hyperresponsiveness to ACTH may be ovarian induced. Reliance on historical controls may lead to overdiagnosis of mild 3 beta-HSD deficiency.

Choroidal vascular abnormality in Purtscher's retinopathy shown by indocyanine green angiography

PURPOSE

To report choroidal vascular abnormality in unilateral Purtscher's retinopathy.

METHODS

Fluorescein angiography and indocyanine green angiography with a scanning laser ophthalmoscope were used to examine a 19-year-old man four days, three months, and five months after sustaining an injury in a car accident.

RESULTS

Indocyanine green angiography showed an area of choroidal hypofluorescence that continued to be present up to five months after the accident.

CONCLUSIONS

Choroidal vasculature may be affected in Purtscher's retinopathy. Disorder in the choroidal microcirculation could be an additional cause of the resulting poor vision observed in some patients with Purtscher's retinopathy.

Incidence of nausea and vomiting in outpatients undergoing general anesthesia in relation to selection of intraoperative opioid

STUDY OBJECTIVE

To measure the incidence of nausea and vomiting in outpatients in relation to selection of, or withholding of, intraoperative opioid.

DESIGN

Prospective, randomized, double-blind control trial.

SETTING

University general hospital.

PATIENTS

200 unpremedicated ASA status 1 and 11 patients, 8 to 80 years old, undergoing general anesthesia for ambulatory surgery.

INTERVENTION

Patients were randomized to four groups, three of which received equipotent doses of different opioids intravenously (i.v.) during induction of anesthesia. Group 1 received nalbuphine 0.25 mg/kg, Group 2, alfentanil 20 ug/kg; Group 3, fentanyl 2 ug/kg; and Group 4, normal saline.

MEASUREMENTS AND MAIN RESULTS

We evaluated (1) incidence and severity of nausea and vomiting in the postanesthesia care unit (PACU) and over the next 24 hours; (2) time to PACU discharge; (3) need for antiemetic therapy; and (4) need for analgesic rescue in the PACU. The incidences of nausea and vomiting were similar in all groups, as were time to discharge, antiemetic, and nonsteroidal antiinflammatory drug requirements. The highest incidences of nausea and vomiting occurred at 6 hours in all groups (23% and 9.5%, respectively). Group 1 required lower rescue doses of morphine in the PACU but this result may have been an artifact due to employing the mixed agonist-antagonist opioid, nalbuphine, in this group.

CONCLUSIONS

Opioid administration at the doses employed during induction of anesthesia does not promote postoperative nausea or vomiting, nor increase length of stay in the PACU.

Receptive field asymmetries and sensitivity to random dot stereograms

The differences between the two monocular receptive fields of cortical cells were measured and compared to their disparity tuning in the awake behaving monkey. Several receptive field properties (direction selectivity, orientation preference, eye preference and response modulation) were determined for each eye using sweeping bright bars. The disparity sensitivity of these cells was also assessed by plotting their response profile, determined for each cell under strictly binocular cyclopean stimulation (dynamic random dot stereograms, RDS). We have found that large differences between the two monocular receptive fields were infrequent and, apparently, not related with the disparity sensitivity profile. We conclude that the monocular asymmetries tested in this study and the sensitivity to positional binocular disparities present in RDS, might be linked to different mechanisms involved in depth perception in the visual system.

The risks, benefits, and costs of expanding donor criteria. A collaborative prospective three-year study

The study purpose was to identify risks, benefits and costs associated with an expanded donor protocol. The protocol design evaluated organs rescued using expanded donor criteria and weighed all costs associated with doing so. Costs were measured against conditions experienced with expanded and traditional criteria and recipient outcome. Traditional donors were between 5 and 55, with negative serologies, and no history of hypertension or diabetes. "Expanded donors" were between 55 and 75 or less than 5, with a history of hypertension, diabetes and/or sero-positive for Hepatitis C. During this study 73 donors met criteria from which 200 organs were transplanted. Defined costs and outcomes for recipients were tracked. Using expanded criteria: costs averaged 20% more per organ; OPO personnel spent an average of 6 hours more time on-site; an additional 12-14 hours in placement activity; and average organs per donor decreased. Heart patient and graft survival rates for traditional and expanded donor organs were comparable. Kidney patients transplanted from this pool experienced a decrease in patient (P = .14) and a significant decrease in graft (P = .02) survival rates. Patient (P = .05) and graft (P = .01) survival rates were significantly lower in liver patients transplanted with expanded donor organs. Two hundred transplants occurred using expanded donor criteria. Costs for the OPO increased appreciably. Heart and kidney utilization from these donors seems justified. It is thought that liver recipients' results were due to utilizing them in sicker patients. Recovery of organs from donors using expanded criteria appears to be a reasonable way of increasing organ supply.

Presentation of endogenous peptide/MHC class I complexes is profoundly influenced by specific C-terminal flanking residues

Processing of intracellular proteins yields 8-11 residue peptides that are displayed on the APC surface as peptide/MHC class I complexes. The remarkably precise excision of antigenic peptides from their precursor polypeptides raises the question of whether specific flanking residues influence presentation efficiency. Here we addressed this question by analyzing the generation of OVA/Kb or influenza nucleoprotein/Db complexes in APC expressing precursors with varying N- or C-terminal flanking residues. We find that T cell responses were not significantly affected by varying the N-terminal flanking residue in the precursors. In contrast, presentation of peptide/MHC complexes was inhibited with the addition of a single C-terminal flanking residue. The most dramatic inhibition was observed with isoleucine, leucine, cysteine, and proline as the C-terminal flanking residues. These residue-specific variations in presentation activity could not be accounted for by differences in the stimulatory activity of corresponding synthetic peptides but were proportional to the relative amounts of naturally processed peptides recovered in the cell extracts. These findings suggest differences in the susceptibility of N- vs C-terminal flanking residues to proteolytic cleavage during Ag processing. The strong influence of specific C-terminal flanking residue(s) could be an important factor affecting the choice of peptides presented to T cells on the APC surface.

Presentation of endogenous peptide/MHC class I complexes is profoundly influenced by specific C-terminal flanking residues

Processing of intracellular proteins yields 8-11 residue peptides that are displayed on the APC surface as peptide/MHC class I complexes. The remarkably precise excision of antigenic peptides from their precursor polypeptides raises the question of whether specific flanking residues influence presentation efficiency. Here we addressed this question by analyzing the generation of OVA/Kb or influenza nucleoprotein/Db complexes in APC expressing precursors with varying N- or C-terminal flanking residues. We find that T cell responses were not significantly affected by varying the N-terminal flanking residue in the precursors. In contrast, presentation of peptide/MHC complexes was inhibited with the addition of a single C-terminal flanking residue. The most dramatic inhibition was observed with isoleucine, leucine, cysteine, and proline as the C-terminal flanking residues. These residue-specific variations in presentation activity could not be accounted for by differences in the stimulatory activity of corresponding synthetic peptides but were proportional to the relative amounts of naturally processed peptides recovered in the cell extracts. These findings suggest differences in the susceptibility of N- vs C-terminal flanking residues to proteolytic cleavage during Ag processing. The strong influence of specific C-terminal flanking residue(s) could be an important factor affecting the choice of peptides presented to T cells on the APC surface.

Bilateral vitreous cysts in an 80-year-old man

Images

Stable expression of human cytochrome P450 2E1 in V79 Chinese hamster cells

A V79 Chinese hamster cell line was constructed for stable expression of human cytochrome P450 2E1 (CYP2E1) by integration of a SV40 Early promoter recombinant CYP2E1 cDNA into the chromosomal DNA. The cDNA encoded CYP2E1 was effectively expressed and enzymatically active, as shown by hydroxylation of chlorzoxazone and of p-nitrophenol, at rates of about 70 pmol x mg-1 total protein x min-1. CYP2E1 content and activity was increased upon cultivation in the presence of ethanol indicating a substrate mediated stabilization effect. A similar stabilizing effect was also observed for inhibitors of CYP2E1, e.g. imidazole, 4-methylpyrazole, and isoniazid. The feasibility of the newly established cell line V79MZh2E1 for toxicological studies was shown by CYP2E1-mediated activation of N-nitrosodimethylamine and p-nitrophenol and a dose-dependent cytotoxic and mutagenic effect.

Reassessment of adrenal androgen secretion in women with polycystic ovary syndrome

OBJECTIVE

To reevaluate the clinical significance of elevations of adrenal androgens in polycystic ovary syndrome (PCOS).

METHODS

Thirty women with PCOS and ten ovulatory controls were evaluated. Serum dehydroepiandrosterone (DHEA) sulfate and 11 beta-hydroxyandrostenedione were measured before and after 3 and 6 months of GnRH agonist (GnRH-A) therapy. All controls and 15 women with PCOS received intravenous ACTH before and after GnRH-A therapy.

RESULTS

Twenty-one (70%) of the women with PCOS had elevations of DHEA sulfate, and 16 (53%) had elevations in 11 beta-hydroxyandrostenedione. Only two women with PCOS had normal values of both adrenal androgens. After GnRH-A therapy, only 11 subjects (37%) had elevated values of DHEA sulfate. Four of 16 women had reductions in 11 beta-hydroxyandrostenedione. Only those with elevated baseline DHEA sulfate levels had reductions after GnRH-A therapy. The reduction of DHEA sulfate with GnRH-A correlated with the reduction in androstenedione. Of the subjects who had reductions in DHEA sulfate with GnRH-A therapy, there was a blunted response of DHEA to ACTH after treatment.

CONCLUSION

Our findings suggest that the ovary may influence the prevalence and magnitude of adrenal androgen excess in PCOS.

Diffuse arterial thrombosis in a young man with elevated lipoprotein(a) and minimal atherosclerosis

An increased incidence of premature atherosclerotic arterial occlusive disease was recently reported in young adults. This condition is characterized by early occurrence of severe symptoms, lower incidence of typical cardiovascular risk factors for atherosclerosis, different natural course of arterial disease vis-a-vis older population, and poor outcome of a standard treatment. This report describes a young man with aggressive arterial occlusive disease in the lower extremities and symptom-free occlusions of coronary and renal arteries in association with high levels of lipoprotein(a). Microscopic early atherosclerotic changes were noted in the occluded arteries of the amputated leg. Premature atherosclerotic arterial occlusive disease in young adults has different clinical and pathological patterns, necessitating a different approach for evaluation and treatment.

Major histocompatibility class I molecules can present cryptic translation products to T-cells

Self or foreign cellular proteins provide peptides for presentation by major histocompatibility complex (MHC) class I molecules on the surface of antigen presenting cells (APC). Surprisingly, several studies have shown that T-cells can recognize APC transfected with antigen genes that were not present in the appropriate translational context. To understand the basis of this phenomenon, APC were transfected with DNA constructs encoding the OVA257-264 (SL8) peptide, but with varying translation initiation codons. We report that, in addition to ATG, 6 other codons (ATT, ACG, CTG, GCG, TGG, GAT) also allowed presentation to SL8-Kb-specific T-cells. Significantly, this set includes 3 of 4 known non-ATG translation initiation codons strongly suggesting that cryptic translation accounts for this phenomenon. Although expression of the SL8-Kb complex was readily detected by T-cell activation, the amount of processed peptides was below detection limit (< 30 copies/cell) in cell extracts. Thus, the fortuitous presence of these cryptic translation initiation sites in transcribed genes can explain how peptide MHC complexes were obtained in sufficient amounts for T-cell activation. The translation initiation codons identified here could also be useful for identifying potential open reading frames that possess biological and/or immunological activities.

Ocular blood flow velocity reduction after buckling surgery

BACKGROUND

It has been reported that scleral buckling reduces the blood flow velocity in retinal vessels. Blood flow changes may also appear in other ocular and extraocular vessels. This study describes the blood flow velocity changes in the ophthalmic artery (OA) after performing this procedure.

METHODS

The study was carried out in 12 patients (12 eyes) with rhegmatogenous retinal detachment. Color Doppler imaging was used to measure the peak and average blood flow velocity in the OA. Measurements were taken 1 day before and 2 days after scleral buckling surgery was performed. Intraocular pressure (IOP) was measured prior to each ultrasound study.

RESULTS

We found that statistically significant reductions in the peak flow velocity (33%) and average flow velocity (31%) occur in the OA after scleral buckling. All patients showed an increase in IOP after surgery.

CONCLUSION

Buckling surgery reduces the blood flow velocity in the OA. Since the OA is the origin of the arterial branches that supply blood to the eye, our results suggest that scleral buckling may decrease not only retinal but also choroidal blood perfusion. Some extraocular structures might also be affected.

Generation of dynamic random-element stereograms in real time with a system based on a personal computer

A new system capable of generating static and dynamic random-element stereograms is designed and implemented. The stereogram is composed of a rectangle that can be varied in size, element density, orientation, and horizontal and vertical disparities, and can be swept at several velocities. The system is based on an inexpensive personal computer (Amiga 500), designed to work as a slave system under the control of a host computer (e.g. any personal computer). A colour monitor or two black and white monitors are suitable display devices to view the stereograms. This system is used to perform psycophysical experiments in humans and neurophysiological experiments in behaving monkeys, with the purpose of studying depth perception and binocular vision.