Acute care hospital utilization by patients with visual impairment

OBJECTIVE

To assess whether visual impairment contributes to average length of stay (ALOS) within inpatient care facilities.

METHODS

We used the New York State Department of Health's Statewide Planning and Research Cooperative System (SPARCS) data for 1993, containing 1 principal diagnosis code and up to 8 secondary diagnosis codes for approximately 2.6 million hospital discharges. We evaluated ALOS differences in patients with and without visual impairment and in patients with eye pathologic conditions, including eye surgery. Visual impairment is not a primary admitting diagnosis, but may be coded as a secondary diagnosis. Eye pathology comprises a large variety of conditions, including corneal ulcers, abscesses, corneal deposits, edema, cataracts, vitreous hemorrhages, and many other eye disorders (ICD-9-CM codes 360-368.9 and 370-379).

RESULTS

The ALOS was 13.4 days for patients with visual impairment (N = 5764), 11.9 days for patients with either eye pathology or visual impairment (N = 60,085), and 8.2 days for patients with no visual impairment (N = 2,546,586). Using a series of multivariate models that controlled for the variables of age, sex, and payer source, as well as disease, disorders, and ophthalmology procedures, we found that the existence of visual impairment added 2.4 days to the ALOS (P<.001), while eye pathology combined with a secondary diagnosis of visual impairment added 1.8 days to the ALOS (P<.001).

CONCLUSIONS

Visual impairment contributes significantly to hospital length of stay. A better understanding of the functional care needs of patients with visual impairment in an acute care setting and at the time of discharge from the hospital may contribute to reducing excess ALOS and its related costs while improving the quality of patient care.

The B regulatory subunit of protein phosphatase 2A is required for completion of macroconidiation and other developmental processes in Neurospora crassa

rgb-1, encoding the tentative B regulatory subunit of the type 2A Ser/Thr phosphatase in Neurospora crassa, was isolated from cDNA and genomic libraries. Based on analysis of cDNA and genomic clones, rgb-1 is 3387 nucleotides in length, contains seven putative introns and encodes a 461-amino-acid polypeptide. Intron I, which is 5' to the presumed translation initiation codon, contains a uORF encoding 34 amino acids. Intron VI undergoes alternative splicing. Inactivation of rgb-1 by the repeat-induced point (RIP) mutation procedure produced progeny that grow slowly, have abnormal hyphal morphology, are female sterile and produce abundant amounts of arthroconidia. The rgb-1RIP strain does not produce major constriction chains or mature macroconidia. Minor constriction chains are formed, yet the growth process reverts to hyphal elongation. Microscopic and genetic analyses indicate that rgb-1 is a regulator of the budding subroutine of the macroconidiation process and that arthroconidiation, which shares common early and late events with macroconidiation, is induced as a default mechanism for asexual reproduction in this fungus.

pzl-1 encodes a novel protein phosphatase-Z-like Ser/Thr protein phosphatase in Neurospora crassa

The gene and cDNA of a novel protein phosphatase were cloned from Neurospora crassa. The pzl-1 gene encompasses three introns and is localized to the left arm of chromosome I between cyt-21 and Fsr-12. It encodes a protein of 58.3 kDa containing a Ser/Pro rich N-terminal segment, and a C-terminal domain that is similar to the catalytic subunit of type 1 protein phosphatases. The first 51 amino acid residues, including a potential N-myristoylation site, as well as the C-terminal domain (about 300 residues) have a high level of sequence identity with yeast PPZ phosphatases. However, residues 52-208 do not share high similarity with other proteins. The mRNA of pzl-1 was detected in all phases of asexual development of the filamentous fungus.

Protein phosphatase 2A is involved in hyphal growth of Neurospora crassa

Cantharidin and calyculin A, natural toxins that are inhibitors of protein phosphatases 1 and 2A (PPI and PP2A, respectively). inhibit Neurospora crassa hyphal growth. When N. crassa was grown in the presence of either drug, abnormalities were observed at hyphal tips. In addition, both drugs induced an increase in hyphal branching. Cantharidin inhibited N. crassa hyphal growth in a temperature-dependent manner, as the effect of the drug was more pronounced at 34 degrees C than at 25 degrees C. In addition to the drug-mediated inhibition of phosphatase activity, a genetic approach was used to determine the phenotypic consequences of reduced PP2A activity. Two strains with subnormal PP2A activity were constructed. The first, in which the original pph-1 gene (encoding the PP2A catalytic subunit) was replaced with an ectopically integrated copy of pph-1, exhibited lower levels of pph-1 transcript, lower PP2A activity and increased sensitivity to cantharidin. Similarly, in a second strain, in which the pph-1 gene was cloned in an antisense orientation downstream of the inducible isocitrate lyase promoter, lower levels of pph-1 transcript, as well as of PP2A activity, and a reduction in hyphal growth were observed. The results of this study indicate that PP2A, and probably other Ser/Thr phosphatases, are involved in the regulation of hyphal growth in N. crassa.

Photoregulation of cot-1, a kinase-encoding gene involved in hyphal growth in Neurospora crassa

Blue light plays a key role as an environmental signal in the regulation of growth and development of fungi and plants. Here we demonstrate that in Neurospora crassa hyphae branch more frequently in cultures grown in light. Previous studies had identified cot-1 as a gene that controls apical hyphal cell elongation. In the cot-1 mutant, cessation of elongation is accompanied by hyperbranching. Here we demonstrate that the cot-1 gene encodes two transcript species of about 2100 nt (cot-1 (s)) and about 2400 nt (cot-1 (l)) in length and that the ratio of both transcript species abundance is photoregulated. The origin of the difference between cot-1 (l) and cot-1 (s) was localized to the 5' end of the cot-1 transcripts, suggesting that two COT1 isoforms with different activities may be formed. Both light effects, on branching and on cot-1 expression, were dependent on functional wc-1 and wc-2 gene products. In addition to light, L-sorbose comprises another environmental cue that controls hyphal branching in N. crassa. In the presence of L-sorbose, photoregulation of cot-1 was blocked, suggesting the involvement of alternative and potentially interdependent signaling pathways for the regulation of hyphal elongation/branching.

ppt-1, a Neurospora crassa PPT/PP5 subfamily serine/threonine protein phosphatase

We isolated a N. crassa cDNA clone encoding a novel-type serine/threonine phosphatase. The gene (mapped to LGVR), designated ppt-1, encodes a 479 amino acid putative polypeptide which contains a conserved tetratricopeptide repeat (TPR) motif. ppt-1 transcript levels are abundant in conidia and decrease during germination, indicating that ppt-1 is developmentally regulated.

Inactivation of a single-2A phosphoprotein phosphatase is lethal in Neurospora crassa

A PCR approach, employing the use of degenerate oligonucleotide mixtures, was used to isolate pph-1, a type-2A protein phosphatase (catalytic subunit)-encoding gene, from Neurospora crassa. The isolated single copy gene is 1327 nucleotides in length, contains four putative introns and encodes a 310 amino-acid polypeptide. pph-1 is located between pdx-1 and col-4 on the right arm of N.crassa linkage group IV. pph-1 transcript levels are highest during the first hours of conidial germination. Failure to obtain viable progeny in which pph-1 had been inactivated via the repeat-induced point (RIP) mutation process, and evidence that nuclei harboring a disrupted pph-1 gene could only be maintained in a heterokaryon, indicated that a functional pph-1 gene is essential for fungal growth. This is the first report providing evidence that inactivation of a single-type-2A protein phosphatase gene results in a lethal phenotype in fungi.