Search PubMed⌕ Search

Biomedical subjects

J D Nelson

Publications and source records attributed to J D Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effects of insulin and EGF on DNA synthesis in bovine endothelial cultures: flow cytometric analysis.

PURPOSE: To investigate the effects of insulin, epidermal growth factor (EGF), and the corneal storage media--DexSol--at 24 and 48 hours on DNA synthesis in confluent primary cultures of bovine corneal endothelial cells. METHODS: Flow cytometry was used to measure changes in DNA synthesis. This technique allows a large number of cells to be counted and sorted into G1, S, and G2/M phases of the cell cycle. RESULTS: Changing the normal culture media to DexSol had no effect on the cell cycle at 24 or 48 hours. The addition of insulin, EGF, or insulin + EGF to DexSol increased DNA synthesis within 24 hours. The mitotic indices for DexSol, DexSol + insulin, and DexSol + EGF were 0.134 (SE = +/- 0.022), 0.207 (+/- 0.027), and 0.205 (+/- 0.052), respectively. Adding insulin + EGF to the DexSol resulted in the most significant change in S and G2/M, increasing the mitotic index to 0.300 (+/- 0.072) (P = 0.0116). At 48 hours, the presence of the growth factors no longer had any effect. CONCLUSIONS: Flow cytometry was a useful technique in separating cultured bovine corneal endothelial cells according to their DNA content. Analysis of the cultures after the addition of insulin and EGF showed an increase in DNA synthesis. The synergistic effects of the growth factors on corneal endothelial cells suggest that they stimulate mitotic activity by different mechanisms. The addition of mitogens to eye bank storage media may increase corneal endothelial cell densities in donor corneas.

Animals↗
PubMed1993

Dermatochalasis and dry eye.

The medical records of 141 patients with dermatochalasis seen during the 32-month period of January 1989 through August 1991 were reviewed. Patients were classified on the basis of symptoms and mode of treatment and were examined for effectiveness of blepharoplasty in ameliorating these symptoms. Seventy-three patients (51.8%) had symptoms similar to those found in keratoconjunctivitis sicca, including mattering, burning, itching, redness, epiphora, foreign-body sensation, and photophobia. Of these 73 patients, 38 (52.1%) underwent upper eyelid blepharoplasty. Subjective improvement in symptoms was achieved in 33 of these patients (86.8%) postoperatively. Upper eyelid blepharoplasty may represent an effective component in the treatment of patients with dermatochalasis and dry-eye symptoms.

Aged↗
PubMed1993

Gram-negative enteric bacillary meningitis: a twenty-one-year experience.

We reviewed our experience with gram-negative enteric bacillary meningitis in neonates and infants from 1969 through 1989. Ninety-eight patients were identified. Their ages were from 1 day to 2 years with a median of 10 days. In 25 patients (26%), predisposing factors were identified, the most common of which were neural tube defects and urinary tract anomalies. The causative agents were Escherichia coli (53%), Klebsiella-Enterobacter species (16%), Citrobacter diversus (9%), Salmonella species (9%), Proteus mirabilis (4%), Serratia marcescens (3%), Bacteroides fragilis (3%), and Aeromonas species (2%). At the time of diagnosis, Gram-stained smears of cerebrospinal fluid revealed gram-negative bacilli in 61% of patients. The causative organism was cultured from blood obtained from 55% of patients, and 21% had positive urine culture results. The cerebrospinal fluid leukocyte counts ranged from 0 to 80,600 cells/mm3, and the cerebrospinal fluid/serum glucose concentration ratio was less than 0.5 in 72% of patients. Antimicrobial regimens varied greatly. After initiation of antibiotic therapy, an average of 3 days was needed for eradication of bacteria from cerebrospinal fluid. The case-fatality rate was 17%, and 61% of survivors had long-term sequelae that included seizure disorders, hydrocephalus, physical disability, developmental delay, and hearing loss.

Anti-Bacterial Agents↗
PubMed1993

Clinical and anatomical study of the effect of transscleral fixation of posterior chamber lenses on early postkeratoplasty astigmatism.

We reviewed the pattern of astigmatism after penetrating keratoplasty and transsclerally sutured posterior chamber lens (TSPCL) placement in 73 patients. Thirty-five patients (48%) had an axis of astigmatism oriented perpendicularly to the haptics of the TSPCL. Twenty-seven patients (37%) had an orientation of astigmatism that was in the same meridian of the haptics of the TSPCL. Eleven patients (15%) had an axis of astigmatism oriented obliquely to the meridian of the haptics of the TSPCL. The distance the haptic fixation sutures were placed behind the limbus appeared to be correlated with the orientation of astigmatism. Patients having the lens fixated within 0.75 mm of the limbus were more likely to have astigmatism oriented perpendicular to the meridian of the haptics of the posterior chamber lens in the early postoperative period. Patients having the lens fixated 2-3 mm posterior to the limbus were more likely to have astigmatism oriented in the same meridian as the haptics of the posterior chamber lens in the early postoperative period. In an eye bank model of TSPCLs during penetrating keratoplasty, the placement of a posterior chamber lens with haptics fixated within 0.75 mm of the limbus significantly widens the recipient bed an average of 0.3 mm in the meridian of the haptics of lens placement (p = 0.02). When the posterior chamber lens haptics were fixated 3 mm posterior to the limbus, the recipient bed was significantly narrowed in the meridian of lens placement an average of 0.2 mm (p = 0.02). It appears that the TSPCLs may have an effect on early postkeratoplasty astigmatism by distorting the corneal wound at the time of keratoplasty.

Aged↗
PubMed1992

Topical fibronectin in the treatment of keratoconjunctivitis sicca. Chiron Keratoconjunctivitis Sicca Study Group.

Topical fibronectin was evaluated for the treatment of keratoconjunctivitis sicca in a multicenter, double-masked, controlled study in which 272 patients were randomly assigned to treatment. Patients with documented clinical evidence of keratoconjunctivitis sicca received either fibronectin, a vehicle alone, or a commercially available artificial tear. Evaluation at baseline, 21, 42, and 63 days consisted of patient self-evaluation of symptoms, rose bengal and fluorescein staining, tear breakup time, Schirmer's testing, and conjunctival impression cytology. Although all groups showed improvements in most study variables during the course of the study, there were no statistically significant differences found between any of the groups. Topical fibronectin does not appear to be more effective than artificial tears in the treatment of keratoconjunctivitis sicca.

Aged↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of selected infections of the skin and skin structure. Infectious Diseases Society of America and the Food and Drug Administration.

No method for classifying infections of the skin and skin structure is uniformly accepted. Therefore, each protocol for the evaluation of new anti-infective drugs must include definitions of the skin and skin-structure infections to be treated. Clinical findings may suggest the etiology. Cultures should be performed by the best available technique. Because the yield of pathogens from sites of skin and skin-structure infection is often low, monitoring of the clinical response to therapy is paramount. Randomized, double-blind, active-control comparative studies are needed, and maintenance of blinding is recommended, even with a change in the route of administration of the study and/or control drugs. The period of follow-up should be defined for each type of infection.

Anti-Infective Agents↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of osteomyelitis in adults. Infectious Diseases Society of America and the Food and Drug Administration.

Cases of osteomyelitis can be divided into four categories: acute hematogenous, vertebral, secondary to a contiguous focus of infection without vascular disease, and secondary to a contiguous focus of infection with vascular disease. Each category may be further divided into acute and chronic forms. Clinical symptoms persisting for > or = 10 days correlate roughly with the development of necrotic bone and chronic osteomyelitis. Patients enrolled in clinical trials should generally be > or = 12 years of age. Prior antimicrobial treatment does not exclude patients if the culture of a bone sample obtained at the time of enrollment yields pathogenic bacteria. Randomized, double-blind, active-control comparative studies are encouraged. Clinical outcome should be assessed during therapy and within 5-9 days, 4-6 weeks, and 11-13 months after completion of therapy. In the final assessment, clinical appraisal is paramount.

Adult↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of acute hematogenous osteomyelitis in children. Infectious Diseases Society of America and the Food and Drug Administration.

Most children with acute hematogenous osteomyelitis have no preceding illness. Their early symptoms are pain and fever. A bacterial etiology is established in approximately 75% of cases by needle aspiration of the affected site or blood culture. Clinical trials should be limited to cases of bacterial origin. The antimicrobial agents studied should be active against Staphylococcus aureus and streptococci. If children < 5 years of age are included, the drug should also be active against beta-lactamase-negative and -positive strains of Haemophilus influenzae. Randomized, prospective, double-blind comparative studies are preferable to open, evaluator-blinded trials. Clinical outcome is appraised by physical signs and symptoms. A successful microbiological outcome consists of presumptive eradication. The final assessment should be made 1 year after completion of therapy.

Acute Disease↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of infectious arthritis in adults. Infectious Diseases Society of America and the Food and Drug Administration.

This guideline describes clinical trials of new anti-infective drugs for the treatment of septic arthritis due to bacteria other than Neisseria gonorrhoeae in adults. Septic arthritis is associated with fever and with physical findings at the affected joint. Diagnosis is established by culture of synovial fluid. Treatment includes the administration of antimicrobial drugs and drainage of the joint by needle aspiration or surgery. Multicenter, randomized comparative clinical trials that are single-, double-, or evaluator-blinded should be performed. However, an open trial of a new antimicrobial agent with historical controls is acceptable. Patients should receive treatment for at least 2-3 weeks. After 5 days of antimicrobial therapy, synovial fluid should be sterile and clinical signs and symptoms should have diminished. Patients should be followed for 2-4 weeks after completion of therapy.

Adult↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of acute suppurative arthritis in children. Infectious Diseases Society of America and the Food and Drug Administration.

Diagnostic criteria for bacterial suppurative arthritis include the demonstration of an inflammatory exudate by aspiration of synovial fluid and the isolation of bacteria from cultures of synovial fluid and/or blood. Clinical manifestations include joint effusion, swelling, tenderness, and pain, with or without redness of the overlying skin. Management consists of antimicrobial therapy, measures designed to relieve symptoms, surgical drainage of infected fluid, and physical therapy. Studies of new anti-infective therapy should be limited to cases of bacterial origin. Prospective, randomized, double-blind, or evaluator-blinded, active-control comparative clinical trials should be performed. Clinical response is characterized as success (cure), failure, or indeterminate outcome. The most common successful microbiological outcome is presumptive eradication. Follow-up should continue for 1 year before the final assessment.

Acute Disease↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of infections of prosthetic hip joints. Infectious Diseases Society of America and the Food and Drug Administration.

Infections of a prosthetic hip are of three types: acute contiguous, chronic contiguous, and hematogenous. Acute contiguous infections result from contamination of the operative field at the time of surgery; clinical manifestations of infection become apparent within 6 months. Chronic contiguous infections are diagnosed 6-24 months postoperatively and are believed to be caused by intraoperative contamination. Hematogenous seeding of prosthetic joints accounts for infections that develop > or = 2 years after surgery. Fever and pain or dysfunction of the joint may be the only signs or symptoms of prosthetic hip joint infection. Definitive diagnosis is established by culture of a needle aspirate from the joint space or by intraoperative culture. Prospective, randomized, double-blind or evaluator-blinded, active-control comparative studies are preferable to open trials. Success rates 10-14 weeks after completion of a 4- to 6-week course of antimicrobial therapy should be > or = 90%.

Adult↗
PubMed1992

Early postkeratoplasty astigmatism following placement of anterior chamber lenses and transsclerally sutured posterior chamber lenses.

Intraocular pseudophakic correction during penetrating keratoplasty (PK) for aphakic or pseudophakic bullous keratopathy may be achieved either with anterior or posterior chamber lenses. Posterior chamber lenses can be fixed to the iris or sclera in eyes lacking adequate posterior capsular support. Post-PK astigmatism can delay early visual rehabilitation of the patient. We reviewed the last 15 patients at our institution who had undergone PK and anterior chamber lens placement for bullous keratopathy. These were compared to the last 15 patients who had undergone PK and transsclerally sutured posterior chamber lens placement. Patients who had placement of a flexible anterior chamber lens at time of PK had a mean astigmatism of 6.73 D at the last visit before any sutures were removed. There was no predominant axis of astigmatism or relationship of the axis of astigmatism to the meridian of lens placement. Patients with placement of a transsclerally sutured posterior chamber lens at time of PK had a mean astigmatism of 5.18 D at the last visit before any sutures were removed. Mean astigmatism was not significantly different (P greater than 0.05) from that seen with anterior chamber lens placement. In the majority of patients the axis of post-PK astigmatism was oriented perpendicular to the meridian of the transsclerally sutured posterior chamber lens.

Aged↗
PubMed1991

Frequency of infections associated with implanted systems vs cuffed, tunneled Silastic venous catheters in patients with acute leukemia.

A total of 75 central venous catheters were used for prolonged chemotherapy in 39 children with acute lymphocytic leukemia and 21 patients with acute myelocytic leukemia. Infection rates were 2.2 per 100 catheter days with the use of cuffed, tunneled, single-lumen Silastic catheters, 2.0 per 1000 catheter days with cuffed, tunneled, double-lumen Silastic catheters, and 0.5 per 1000 catheter days with the use of implanted venous access systems. Eighty-one percent of catheter sepsis episodes were successfully treated without removal of the catheter. All tunnel infections required withdrawal of the catheter for cure. The microorganisms were gram-positive bacteria in 15%, gram-negative bacteria in 7%, and fungi in 4%. Coagulase-negative staphylococci and Pseudomonas aeruginosa were the most commonly isolated organisms. Three of six fatal sepsis episodes were caused by disseminated fungal infections. We conclude that the use of intracorporeal venous catheter systems in patients with acute lymphocytic leukemia is associated with a lower infection rate than that with cuffed, tunneled Silastic single- or double-lumen catheters and that most septicemias can be cured with antimicrobial therapy without removal of the catheter.

Adolescent↗
PubMed1991

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study five years after surgery. The Perk Study Group.

In the Prospective Evaluation of Radial Keratotomy (PERK) Study, 793 eyes of 435 patients with 2 to 8 diopters (D) of myopia received a standardized surgery consisting of 8 incisions with a diamond-bladed knife set at 100% of the thinnest paracentral ultrasonic corneal thickness measurement and a diameter of the clear zone of 3.0 to 4.5 mm; 97 eyes (12%) received an additional 8 incisions. There were 757 eyes (95%) followed for 3 to 6.3 years. After surgery, uncorrected visual acuity was 20/40 or better in 88% of eyes. The refractive error was within 1 D of emmetropia for 64% of eyes; 19% were myopic and 17% were hyperopic by more than 1 D. Between 6 months and 5 years after surgery, 22% of the eyes had a refractive change of 1 D or more in the hyperopic direction. For 25 eyes (3%) there was a loss of 2 or more lines of best spectacle-corrected visual acuity.

Adult↗
PubMed1991

Comparative evaluation of loracarbef and amoxicillin-clavulanate for acute otitis media.

One hundred five infants and children with acute otitis media were randomized to therapy with loracarbef, an experimental carbacephem antibiotic, or amoxicillin-clavulanate (Augmentin), an approved drug for this disease. Ninety-two were evaluable (46 in each group). Middle ear fluid samples obtained for culture before therapy grew Haemophilus spp. in 30% of cases, pneumococci in 29% of cases, and Moraxella catarrhalis in 15% of cases. beta-Lactamase-producing bacteria were found in 37% of patients. Clinical failure occurred in four loracarbef-treated patients and one amoxicillin-clavulanate-treated patient (P = 0.361). Recurrence of acute otitis media was more common in the 2 to 3 weeks after loracarbef treatment (eight patients) than it was after amoxicillin-clavulanate therapy (three patients), but not significantly so (P = 0.197). Thus, combined failure and recurrence occurred in 12 loracarbef-treated patients and four amoxicillin-clavulanate-treated patients (P = 0.052). Gastrointestinal side effects occurred in 13 loracarbef-treated and 21 amoxicillin-clavulanate-treated patients (P = 0.13). Diaper rash was more common with amoxicillin-clavulanate (22 patients) than with loracarbef (10 patients; P = 0.016). Satisfactory results were achieved with both antibiotics, and adverse effects, although common, were minor.

Acute Disease↗