Threshold versus intensity functions in two-colour automated perimetry

PURPOSE

Two-colour computerised perimetry is a technique developed for assessing cone- and rod-function at fixed background luminances in retinal disease. However, the state of adaptation during testing is unknown but crucial in the interpretation of results. We therefore aimed to determine the adaptational state of rod- and cone-mechanisms in two-colour perimetry.

METHODS

Sensitivity to 480 nm (blue) and 640 nm (red) Goldmann size V targets was determined for 10 normal subjects aged 16 to 46 years at 17 locations in the central 60 degrees of the visual field under scotopic conditions and then from -1.5 log cd m^-2 to 2 log cd m^-2 (white background) in 0.5 log unit steps. Data were fitted with threshold versus intensity (tvi) functions of the form logT = logT₀ + log ((A + A₀ )/A₀ )ⁿ .

RESULTS

No clear rod-cone break was observed for 640 nm stimuli. For 480 nm stimuli, transition from rod-detection to cone-detection occurred at mesopic illumination levels, where rod adaptation approached Weber behaviour. Cone detection mechanisms did not display Weber-like adaptation until the background luminance approached 1 log cd.m^-2 . Diseases resulting in a "filter effect" - including disorders of the photoreceptors - are therefore predicted to affect sensitivity when rod function is probed with short-wavelength targets under scotopic conditions, but less so under mesopic conditions. Filter effects are similarly anticipated to affect cone function measured using long-wavelength targets under mesopic conditions (e.g., during microperimetry), but less so under photopic conditions.

CONCLUSIONS

Asymmetries in adaptation in automated two-colour perimetry are predicted to artefactually favour the detection of losses in rod sensitivity under scotopic conditions and cones under mesopic conditions.

Retinal detachments in southern New Zealand: do poorer patients have poorer outcomes?

AIMS

To investigate associations between socioeconomic status, retinal detachment type and post-operative visual outcomes in southern New Zealand. 

METHODS

A retrospective review of all cases of rhegmatogenous retinal detachments in Dunedin Hospital over two years was performed. Patient demographics and macula involvement at presentation were the primary outcome measures. The New Zealand Deprivation Index was used to group patients into low (30% least deprived), medium (middle 40%) and high (30% most deprived). Patients were excluded if they were not from New Zealand, or had traumatic detachments. 

RESULTS

During the study period, 95 retinal detachments in 94 patients were managed in Dunedin Hospital. Only 15% of retinal detachments occurred in the most deprived. More deprived patients had longer delays before assessment in hospital (mean of 29.8 days versus 10.1 days for the least deprived and 12.8 days for the medium category, overall p=0.025). There was no evidence of an association between deprivation and macula-off status (overall p=0.650) or visual acuity at one or three months (p=0.063 and p=0.328 respectively). Nor was there an association between referral pathway and macula-off status (p=0.242).

CONCLUSIONS

Retinal detachment in southern New Zealand may be less common amongst those with the most deprived socioeconomic status who also experience longer delays till first treatment; but there was no association between socioeconomic status and patients being macula-off at presentation, or having poorer visual outcomes. More targeted patient education towards our most deprived citizens may reduce delays in treatment, and result in better visual outcomes.

Progression of diabetic maculopathy in patients on the Wellington Diabetic Screening Programme initially graded M3

AIM

To determine the likelihood of progression from M3 grade maculopathy, and therefore the safety of these patients remaining under the care of a primary screener.

METHODS

Patients graded M3 at diabetic screening were selected from the Wellington screening database. Photographs for this visit and the subsequent visit were obtained, and graded by a consultant ophthalmologist. Photographs graded M3 were included and progression of maculopathy between visits, number of patients with a reduction in vision and duration between visits were determined.

RESULTS

Mean duration between visits for all patients was 255 (plus or minus 59.5) days. Of the 54 eyes studied, 15 or 33.3% progressed to M4 maculopathy at the subsequent visit. Despite progressing from M3 to M4, none had a reduction of vision by more than one line of Snellen acuity at follow up due to diabetic maculopathy.

CONCLUSIONS

Rates of progression of maculopathy from M3 to M4 were of clinical significance. Despite this none had worsening visual acuity due to diabetic eye disease. This suggests patients with M3 maculopathy could be maintained under a primary screening programme, as is the case in the United Kingdom.

Repeatability of primary selective laser trabeculoplasty in patients with primary open-angle glaucoma

To determine if primary selective laser trabeculoplasty (SLT) can be repeated with clinical benefit in patients with primary open-angle glaucoma (POAG). Forty-two eyes of 42 patients with POAG were studied. All patients underwent primary SLT treatment of 40-50 shots to the trabecular meshwork over 360°. The treatment response at the initial post-SLT visit (4 weeks), and second post-SLT visit (mean 4 months), clinical success and duration of clinical success were measured. SLT was repeated in all patients after failure to maintain target intraocular pressure (IOP). The same parameters were measured after repeat SLT. The main outcome measures were success of treatment (as defined by reduction of IOP by at least 20 % and below an individually determined target pressure), duration of treatment success and reduction in IOP. No significant difference between initial and repeat treatments was found for mean reduction in IOP or success rate, or duration of success. Survival analysis found significantly longer benefit for repeat treatment compared to initial treatment (P < 0.01). Repeat SLT treatment in eyes with POAG has similar efficacy to primary SLT treatment with respect to reduction in IOP and success rates, produces a longer duration of treatment success.

The 'Dr Google' phenomenon--missed appendicitis

Self-diagnosis has been around for many years. In today's society with free access to information, particularly through the Internet, it is more prominent than ever. With new information sources available to patients, doctors may have their diagnostic process influenced. This is the case of a gentleman who self-diagnosed, and subsequently influenced his doctor's diagnostic process, with results detrimental to his outcome. It illustrates the importance of awareness of the risks of self diagnosis, and management of patients who present with information and preconceived ideas regarding their condition.

Pulmonary eosinophilia correlates with allergen deposition to the lower respiratory tract in a mouse model of asthma

BACKGROUND

Eosinophilic infiltration into the airways is frequently associated with allergic asthma; however, the role of antigen deposition in mediating this phenomenon has not been studied in detail.

OBJECTIVE

Using a murine model of ovalbumin (OVA) allergy, we examined how differential deposition of OVA during antigen challenge affects pulmonary eosinophilia, immune response and airway hyper-reactivity (AHR).

METHODS

Differential allergen deposition to the upper respiratory tract (URT) alone or combined upper and lower respiratory tract (ULRT) was accomplished by administering OVA intranasally to either anaesthetized or unanaesthetized mice, respectively. BALB/c mice (6-7 weeks old) were sensitized with OVA-alum via the intraperitoneal route, and then challenged intranasally using OVA, with or without anaesthesia. AHR, enumeration of inflammatory cells and quantitative measurement of inflammatory cytokines and chemokines in bronchoalveolar lavage fluid (BALF), lung histopathology and immune responses were subsequently assessed.

RESULTS

In sensitized animals challenged via the ULRT route, a profound eosinophilia and goblet cell hyperplasia was observed in lung tissue. Conversely, sensitized mice receiving an identical challenge dose via the URT route alone exhibited only negligible levels of inflammation. Interestingly, AHR and OVA-specific IgG(1) and IgE systemic responses were comparable between the two groups.

CONCLUSION

This study indicates that direct exposure of allergen in the deep lung is highly correlated with airway eosinophilia and lung inflammation, but does not correlate with AHR or immune response.

The addition of fentanyl does not alter the extent of spread of intrathecal isobaric bupivacaine in clinical practice

PURPOSE

Fentanyl is commonly added to intrathecal local anesthetic solutions. In vitro data has shown fentanyl to render isobaric local anesthetics hypobaric, and alter the spread in artificial cerebrospinal fluid. This study examined whether the addition of fentanyl to isobaric bupivacaine with morphine leads to a clinically important alteration in the extent of spread of anesthesia.

METHODS

Forty-four ASA I-III patients undergoing lower limb orthopedic procedures completed this double-blind, placebo-controlled trial. Patients were randomized into one of two groups, receiving intrathecal bupivacaine 15 mg and preservative-free morphine 200 microg without (Control group), or with the addition of fentanyl 0.02 mg (Fentanyl group). Patients were maintained at a slight head-up tilt. Variables studied over three hours included sensory level to cold and pinprick, motor blockade (Bromage scale), and circulatory data.

RESULTS

No differences existed between the Fentanyl and Control groups with respect to highest level of block for cold: T4 (T2-T5) vs T3.5 (T3-T8) respectively (median, 95% confidence interval) or pinprick: T4 (T3-T6) vs T4.5 (T3-T8). Similarly, there was no difference in the time taken to reach maximum block height to cold (20 +/- 9 vs 23 +/- 13 min, mean +/- SD) or pinprick (20 +/- 9 vs 24 +/- 13 min).

CONCLUSION

The addition of fentanyl 0.02 mg to 0.5% bupivacaine with morphine does not affect the maximal block height or time to maximal block in clinical practice.

Absorption of alkalized intravesical lidocaine in normal and inflamed bladders: a simple method for improving bladder anesthesia

PURPOSE

Pharmacokinetic studies have shown that intravesical lidocaine is not sufficiently absorbed by human bladders to achieve significant serum levels and it only provides a superficial local anesthetic effect. We investigated the pharmacokinetics of alkalized intravesical lidocaine in healthy volunteers and patients with interstitial cystitis to determine a safe dose of buffered lidocaine, the effect of interstitial cystitis on lidocaine uptake and the acute local anesthetic effect on bladder pain in interstitial cystitis.

MATERIALS AND METHODS

An initial dose finding study was done in 12 healthy volunteers using 4, 5 and 6 mg./kg. 5% lidocaine buffered with 8.4% sodium bicarbonate. Serial lidocaine levels were measured for 3 hours. Serum measurement was repeated in 12 patients with interstitial cystitis using 5 mg/kg. 5% lidocaine with sodium bicarbonate daily for 2 days. Patients rated pain before and during treatment.

RESULTS

Healthy volunteers and patients with interstitial cystitis had similar lidocaine absorption profiles with a peak of 1.06 microg/ml. (range 0.66 to 1.71) and 1.3 (range 0.2 to 2.0) at about 30 minutes. Mean pain score in the interstitial cystitis group decreased from a baseline of 6.0 to 1.8 on day 1 and 0.6 on day 2. There were complaints of urethral discomfort after voiding the buffered lidocaine in each group.

CONCLUSIONS

Alkalization provides safe and predictable lidocaine absorption into the bladder, as indicated by therapeutic systemic levels in healthy and inflamed bladders. Furthermore, the decrease in acute pain scores in the interstitial cystitis group indicated a concentration of local anesthetic within the bladder wall that was sufficient to block the sensory neurons within the submucosal plexus.

Sex in the consulting room, the examining room, and the sacristy: survivors of sexual abuse by professionals

The impact on 149 survivors of sexual abuse by medical and mental health professionals and clergy was compared. Loss, emotional turmoil, mistrust, depression, relationship difficulties, and difficult complaint procedures were reported by all three groups, with survivors of abuse by medical health professionals reporting the most pronounced negative effects. Implications for subsequent mental health treatment of survivors from all three abuse groups are explored.

Fibrin sealant: clinical use and the development of the University of Virginia Tissue Adhesive Center

The utilization of fibrin sealants to augment hemostasis, seal tissues, and facilitate targeted delivery of drugs is increasing. In 1985, a hospital-based program was established to provide autologous and allogeneic cryoprecipitate that serves as a fibrin sealant when combined with bovine thrombin. To date, more than 4,000 patients have been treated with this product at our institution, with an efficacy rate greater than 90%. Collaboration among surgical services and the blood bank fostered multispecialty expertise with this product that led, in 1997, to the establishment of the University of Virginia Tissue Adhesive Center. The Tissue Adhesive Center is a multidisciplinary center whose physician director and nursing and administrative support staff facilitate basic research, laboratory investigation, and preclinical and clinical trials with collaborators throughout the university. The Tissue Adhesive Center also provides educational programs and clinical consultation, and tracks and participates in peer review of sealant use. The licensure of a commercially produced, virally inactivated, pooled-plasma fibrin sealant in May 1998 provided an alternative source of adhesive. Utilization of the commercial product surpassed use of the blood bank product in April 1999. At present, use of the commercial product is approximately 3 times that of the blood bank-produced sealant. This report reviews the clinical uses of fibrin sealant, its regulatory history, the production of fibrin sealants, the evolution of a blood bank fibrin sealant program, the development of the Tissue Adhesive Center, and the utilization of commercial and blood bank-produced sealant at our university hospital.

Informed consent for labour epidurals: what labouring women want to know

PURPOSE

To determine A) what a labouring woman expects to hear about epidural analgesia before consenting, B) if she feels able to understand the risks and thereby assess if we are obtaining informed consent.

METHODS

Sixty actively labouring women were surveyed immediately after requesting an epidural. Demographic, labour, epidural and consent information were included in the questionnaire. Answers were categorical (yes/no, multiple choice) or scored on a scale from 0 to 10 (visual analogue scale).

RESULTS

The majority of parturients wanted all potential epidural complications but not their incidences disclosed in the consent process. However, a discussion of risks would not dissuade women from consenting to an epidural in the majority of cases. Labouring women have a moderate understanding of epidural risks. The ability to understand risks was not affected by labour pain, anxiety, opioid premedication, duration of labour pain, desire for an epidural, previous epidural experience, level of education or age.

CONCLUSION

This prospective survey characterizes what 60 reasonable labouring women wanted to know about labour epidural analgesia. Parturients wanted all risks of epidural analgesia disclosed in the informed consent process. The majority of women did not want the incidences quoted. This study suggests that labouring patients are as able to give informed consent as are other members of our patient population.

A fully automated blood typing system for hospital transfusion services. ABS2000 Study Group

BACKGROUND

The results of routine blood bank testing by a fully automated blood typing system (ABS2000) were compared with those obtained by standard manual methods in six hospital transfusion services.

STUDY DESIGN AND METHODS

The ABS2000 system uses microtiter plates for determining ABO and D types, solid-phase red cell adherence (SPRCA) assays for antibody detection, and modified SPRCA plates for IgG crossmatches. The transfusion services used their standard manual test tube methods.

RESULTS

Of 3779 donors' samples tested for ABO types (red cell typings only), 3.0 percent could not be interpreted by the ABS2000 system's neural network, because of clots, hemolysis, or lipemic samples. The results for ABO types were concordant for 99.8 percent of the remaining samples. Of 3779 donors' samples tested for D types, the results were concordant for 98.7 percent. Of 7580 patients' samples tested for ABO types (red cell and plasma typings), 5.8 percent could not be interpreted by the ABS2000 system. There was 100-percent concordance of ABO typing results for the remaining 7140 samples. There was 99. 7-percent concordance of results for patients' D types. The results of 96.7 percent of antibody detection tests and 98.8 percent of crossmatches were concordant. Neither method failed to detect a serologically incompatible crossmatch that was associated with a specific, clinically significant alloantibody. The ABS2000 system performed 45 confirmatory donor ABO and D types in 115 minutes, 22 antibody detection tests in 116 minutes, 16 patients' ABO/D types in 149 minutes, and 40 crossmatches in 140 minutes.

CONCLUSION

The ABS2000 blood typing system automates routine blood bank tests with accuracy comparable to that of hospital transfusion services' standard manual methods.

Dopamine D(2) receptor ribozyme inhibits quinpirole-induced stereotypy in rats

The injection of a dopamine D(2) receptor hammerhead ribozyme (20 microg) once daily for 5 days into the nucleus accumbens of rats resulted in an inhibition of stereotyped sniffing and locomotor activation produced by the selective dopamine D(2) receptor agonist, quinpirole (0.4 mg kg(-1) s.c.). The results suggest that ribozymes may be useful in the study of in vivo gene function in the brain.

Rhesus rhadinovirus establishes a latent infection in B lymphocytes in vivo

Recent DNA sequence analysis indicates that rhesus rhadinovirus (RRV) is a member of the lymphotropic gamma-2 herpesvirus family. To determine if RRV is lymphotropic, peripheral blood mononuclear cells from naturally infected monkeys were separated by immunomagnetic bead depletion and analyzed for the presence of RRV by virus isolation and nested PCR. The recovery and consistent detection of RRV in the CD20(+)-enriched fraction clearly demonstrates that B lymphocytes are a major site of virus persistence.

Post discharge nausea and vomiting after ambulatory laparoscopy is not reduced by promethazine prophylaxis

PURPOSE

To determine the incidence of post-discharge nausea and vomiting (PDNV) following outpatient laparoscopic procedures in women, and to assess the efficacy of the prophylactic administration of promethazine prior to discharge from hospital.

METHODS

Ninety-five healthy women scheduled for ambulatory laparoscopic cholecystectomy or gynecological surgery completed this double blind, placebo controlled study. A standardized fentanyl-propofol-nitrous oxide-isoflurane anesthetic was used, and all patients received 0.5 mg droperidol i.v., intraoperatively. Subjects were randomized to receive 0.6 mg x kg(-1) promethazine or placebo i.m. prior to transfer from the post-anesthetic recovery (PAR) unit. The incidence and severity of nausea, pain, and drowsiness were documented using patient diaries at four time intervals during the first 24 hr postoperatively using four-point self-assessment scales.

RESULTS

After discharge home, the overall incidence of nausea was 48%, moderate to severe nausea 30%, vomiting 17% and rescue antiemetic use 28%, with no difference between those receiving saline or promethazine. The need for antiemetics in the PAR was associated with subsequent PDNV, with those requiring PAR antiemetics being four times as likely to vomit after discharge (P = 0.008).

CONCLUSION

Despite the prophylactic administration of 0.5 mg droperidol i.v., patients undergoing ambulatory laparoscopic surgery reported a high incidence of nausea after discharge. Patients requiring antiemetics in the PAR were at higher risk for PDNV. The incidence of nausea was not altered by prophylactic administration of 0.6 mg x kg(-1) promethazine i.m. before discharge.

Changes in collagen cross-linking in degenerative disc disease and scoliosis

STUDY DESIGN

Biochemical study of the changes in the collagen cross-link profile of human intervertebral discs collected at surgery from patients with either low back pain associated with disc degeneration or scoliosis.

OBJECTIVE

To determine whether changes occur in the collagen cross-link profile in the disc of patients with either low back pain associated with disc degeneration or scoliosis, which may well influence matrix integrity. Such changes in the cross-link profile of a tissue indicates increased matrix turnover and tissue remodeling and may have implications for the progression of these disorders.

SUMMARY OF BACKGROUND DATA

The diseases of the intervertebral disc, degenerative disc disease and scoliosis, are both characterized by changes in the extracellular matrix components that will affect the mechanical function of the tissue. The stability of the collagenous components and hence the mechanical integrity of connective tissues such as the disc is dependent on the degree and type of cross-links between the collagen molecules. This article reports results on the distribution of the different cross-links in the disc and the changes that occur with age, degenerative disc disease, and scoliosis.

METHODS

Thirty-three discs were obtained from patients with degenerative disc disease and 29 discs from patients with scoliosis. Samples were acid hydrolyzed and the collagen cross-links analyzed by either fractionation on an amino acid analyzer configured for cross-link analysis using ninhydrin postcolumn detection or fractionation by high-pressure liquid chromatography with fluorescence detection.

RESULTS

The reducible cross-links and the mature cross-link all increased from the outer anulus fibrosus through into the nucleus pulposus. The highest levels of the mature cross-link were found in the cartilage end-plate. The nonenzymic derived cross-link, pentosidine, in contrast, showed little difference across the disc, but did show the expected age-related increase. In degenerative disc disease, no change in the levels of the reducible or mature cross-links was found, but a decrease was observed in the levels of the age-related cross-link pentosidine in the more severe disease samples. In scoliosis, significantly higher levels of the reducible cross-links were found on the convex than on the concave side of the scoliotic disc.

CONCLUSIONS

These changes in the cross-link profile of the intervertebral disc in degenerative disc disease and scoliosis are indicative of increased matrix turnover and tissue remodeling and likely to have implications for the progression of these disorders.

Rapid preparation of small-volume autologous fibrinogen concentrate and its same day use in bleb leaks after glaucoma filtration surgery

The authors evaluated small-volume preparation of autologous fibrin glue (AFG) and same day use in postglaucoma filtration surgery patients with Seidel positive bleb leaks and determined fibrinogen concentrations in autologous fibrinogen concentrates (AFCs) from 10 volunteers. Thirty milliliters of blood was centrifuged (5 min, 2400 x g); plasma was frozen (5 min-ethanol and ice), thawed (1-6 C, 30-60 min), and centrifuged (10 min, 5 C, 2800 x g); and the precipitate was transferred to a 1.0-ml tuberculosis syringe. Thrombin (1000 U) was dissolved (0.8 sterile water, 0.2 ml aminocaproic acid) and warmed (37 C). Average preparation time was 90 minutes. Alternating drops of AFC and thrombin were applied to bleb leaks until AFC clotted. Seidel testing with fluorescein determined success. AFC was prepared from 10 volunteers and fibrinogen was measured. AFG was initially successful with two (Seidel negative) eyes; one eye remained negative. AFG was unsuccessful in one briskly Seidel-positive leak. Mean +/- SD fibrinogen concentration in AFCs from the 10 volunteers was 2314 +/- 643 mg/dl (range 1608-3431 mg/dl). AFG may successfully close bleb leaks in outpatient settings. Brisk aqueous flow may impair effectiveness of AFG. Fibrinogen concentrations were comparable with previous reports.

Evaluation of CAPTURE CMV solid phase testing over the allowable shelf-life of red blood cells (adenine-saline added)

BACKGROUND

CAPTURE CMV (IMMUCOR Inc., Norcross, GA) is a solid-phase screening test used to detect IgM and IgG antibodies to cytomegalovirus (CMV). CAPTURE CMV is licensed for testing whole blood (WB) in citrate phosphate dextrose (CPD) preserved segments of units of red blood cells (RBC) only up to 7 days of storage. We determined if CAPTURE CMV could produce consistent results in CPD preserved WB segments from RBC adenine-saline added (ASA) for their 42 day shelf-life.

METHODS

Ten CMV-seropositive and 10 CMV-seronegative RBC (ASA) tested by CAPTURE CMV during the first week of storage were studied. Segments were tested weekly for 6 weeks.

RESULTS

All 10 units that initially tested as CMV-seropositive remained strongly seropositive. All 10 units initially CMV-seronegative, remained seronegative.

CONCLUSION

CAPTURE CMV testing provides consistent results over the entire shelf-life of RBC (ASA).

Fibrin sealant: an evaluation of methods of production and the role of the blood bank

Blood banks can prepare fibrin sealant by several methods. Allogeneic components allow for banking of the fibrinogen concentrate for immediate use. Autologous components eliminate the risk of transfusion-transmitted disease to the recipient, but not necessarily to the preparer. Ethanol and ammonium sulfate precipitation of fibrinogen concentrate allow use of autologous blood and fast preparation (less than 90 minutes). Cryoprecipitation from liquid plasma is adequate, conserving fresh frozen plasma. Cryoprecipitation by the "freeze-thaw" method has been reported to have the highest fibrinogen yield (7840 mg/dL +/- 1800 mg/dL), whereas ammonium sulfate precipitation has been reported to have the highest bonding strength (41 g/cm2 10 minutes after thrombin addition). Cost, storage, preparation time, and transfusion-transmitted disease all play a role in choice of method.

Simian AIDS type D serogroup 2 retrovirus: isolation of an infectious molecular clone and sequence analyses of its envelope glycoprotein gene and 3' long terminal repeat

We describe the molecular cloning of a serogroup 2 simian retrovirus (SRV; D2/RHE/OR) and present the sequence of its envelope (env) glycoprotein gene and 3' long terminal repeat region. This report documents the first infectious molecular clone of a serogroup 2 SRV and provides env sequence verification of genetic diversity among serogroup 2 SRV isolates.

Changes in the collagenous matrix of the aging human lamina cribrosa

AIMS

The age-related changes in the biochemical composition of the collagenous matrix of the human lamina cribrosa were investigated.

METHODS

An age range (3 weeks to 92 years old) of human laminae cribrosae, dissected free of any surrounding structures which contained collagen, were analysed for collagen solubility (n = 58) total collagen content (n = 46), proportion of collagen types (n = 38), and collagen cross linking (n = 30), using hydroxyproline analysis, scanning densitometry of peptides after cyanogen bromide digestion, and high performance liquid chromatography, respectively.

RESULTS

Age-related changes included an increase in total collagen and a decrease in the proportion of type III collagen within the lamina cribrosa. The collagen cross link pyridinoline was present at low levels, but demonstrated no trend with age. An age-related increase was found in pentosidine, an advanced glycation product.

CONCLUSION

These changes in collagen composition imply that the mechanical properties of the lamina cribrosa are altered, resulting in a stiffer, less resilient structure with age. Such alterations in structure may contribute to the increased susceptibility of the elderly to axonal damage in chronic open angle glaucoma.

Polymerase chain reaction detection of type D simian retrovirus proviral DNA from infected macaques

A simple polymerase chain reaction (PCR) approach was developed for detection of Type D simian retrovirus (SRV) serogroup 2 proviral DNA using peripheral blood lymphocytes (PBLs) obtained from infected macaques. PCR primer pairs were developed against serogroup 2 envelope (env) gene sequence, and fidelity of PCR fragment amplification was determined using molecularly cloned SRV serogroup 2 (D2/RHE/OR) DNA, and genomic DNA from Raji cells independently infected with different SRV serogroups. One primer pair exhibiting high fidelity was then utilized for PCR detection of serogroup 2 proviral DNA from PBLs, and from cells sorted into immune cell subpopulations by fluorescent-activated cell sorting (FACS). Env PCR fragments were readily detected from as few as 10(4) PBLs or immune cell subpopulations. In addition, highly specific PCR primers against serogroups 1 and 3 were utilized to detect proviral DNA from Raji cells infected with SRV serogroups. In all cases, primers designed to amplify serogroups 1, 2, and 3 proviral DNA were specific for their intended serogroup. This primer information and development of a PCR approach for detection of specific SRV proviral DNA will be of potential utility as a rapid surveillance tool in monitoring type D simian retrovirus infection within Asian macaque colonies.

Fibrin glue from stored human plasma. An inexpensive and efficient method for local blood bank preparation

European surgeons have used fibrin glue extensively during thoracic, cardiovascular, and general surgical operations. Until now, however, it has been available only as a commercial preparation made from pooled human plasma, and it has not been approved by the U.S. Food and Drug Administration for use in the United States because of a high associated risk of hepatitis and acquired immune deficiency syndrome. Methods of obtaining fibrinogen, an essential component of fibrin glue, from cryoprecipitate or fresh frozen plasma have been published recently. However, the cryoprecipitate method results in relatively low concentrations of fibrinogen, which can reduce glue effectiveness. The fresh frozen plasma method is more expensive and does not meet the standards of the American Association of Blood Banks for the "closed" system required for safe handling and management of blood component products. Both the cryoprecipitate and the fresh frozen plasma methods result in waste of unstable clotting factors. These factors are necessary to replace human plasma clotting deficiencies but are not necessary for the production of fibrin glue. The authors have developed an efficient, high-concentration blood bank method for producing and maintaining a local supply of a safer and less expensive but equally effective material derived from stored human plasma. This material is produced using approved blood bank techniques for a "closed" system in blood component production, thus reducing the risks of contamination and infection, and its fibrinogen concentration is higher than that of standard cryoprecipitate. The cost of 1 unit of this fibrin glue is comparable to that for 1 unit of cryoprecipitate and less than that for 1 unit of fresh frozen plasma.(ABSTRACT TRUNCATED AT 250 WORDS)