Evaluation of oxytetracycline leaching from pregelatinized starch-coated medicated fish feed

The rapid growth and intensification of aquaculture industries have led to an increased use of antibiotics. Consequently, growing concerns have mounted over the environmental contamination of these drugs from medicated feeds and the risk that this poses for antimicrobial resistance. To circumvent environmental leaching, farmers topcoat medicated feeds with oil; however, this only partially addresses the issue. This study investigated the potential of food-grade pregelatinized corn starch (PGS) as a second top-coating agent to reduce oxytetracycline (OTC) leaching from the hand-mixed medicated feed. We immersed top-coated medicated feeds for different periods of time and measured the concentration of OTC in the water to determine leaching. We found a significantly lower level of OTC in water samples collected from the PGS-coated medicated feed compared to the non-PGS-coated medicated feed, with concentrations of OTC approximately 4 and 2.6 times the latter after 5 min and 2 h of water immersion, respectively. We also fed PGS-coated antibiotic feed to jade perch to determine if fish accepted the top-coating and whether they absorbed the OTC. Results from a feeding trial suggested no difference in palatability between PGS and non-PGS-coated medicated feed. We also found that muscle tissue from fish fed with the aforementioned diets had similar levels of OTC concentrations, suggesting that PGS coating does not alter the gastrointestinal absorption of this medication. From our experiment, we conclude that PGS is potentially a new top-coating agent to reduce leaching in hand-mixed OTC medicated feed.

ALEXIS O-Ring wound retractor vs conventional wound protection for the prevention of surgical site infections in colorectal resections(1)

AIM

Surgical site infection (SSI) remains a common postoperative morbidity, particularly in colorectal resections, and poses a significant financial burden to the healthcare system. The omission of mechanical bowel preparation, as is performed in enhanced recovery after surgery programmes, appears to further increase the incidence. Various wound protection methods have been devised to reduce the incidence of SSIs. However, there are few randomized controlled trials assessing their efficacy. The aim of this study is to investigate whether ALEXIS wound retractors with reinforced O-rings are superior to conventional wound protection methods in preventing SSIs in colorectal resections.

METHODOLOGY

Patients undergoing elective open colorectal resections via a standardized midline laparotomy were prospectively randomized to either ALEXIS or conventional wound protection in a double-blinded manner. A sample size of 30 in each arm was determined to detect a reduction of SSI from 20% to 1% with a power of 80%. Secondary outcomes included postoperative pain. The operative wound was inspected daily by a specialist wound nurse during admission, and again 30 days postoperatively. Statistical analysis was performed using spss version 13 with P < 0.05 considered significant.

RESULTS

Seventy-two patients were recruited into the study but eight were excluded. There were no SSIs in the ALEXIS study arm (n = 34) but six superficial incisional SSIs (20%) were diagnosed in the control arm (P = 0.006). Postoperative pain score analysis did not demonstrate any difference between the two groups (P = 0.664).

CONCLUSION

The ALEXIS wound retractor is more effective in preventing SSI in elective colorectal resections compared with conventional methods.

A protocol for measuring ophthalmologic morbidity and recovery after cranial base surgery

Patients with cranial base tumors often have impairment in visual function, either due to the pathologic process itself or as a result of surgical treatment of the lesion. We conducted a pilot study in which we performed ophthalmologic evaluations on patients before and after cranial base surgery. The results of the study were used to develop a protocol and reporting form for longitudinal assessment of visual function in these patients. Use of the protocol and reporting form for the past 2(1/2) years has shown that they are easy for physicians to use and that the results provide a representative evaluation of the patient's ability to function visually in everyday life. The authors propose implementation of the protocol and reporting form as a means of collecting data for further research into visual function in patients with cranial base tumors.

Secondary intraocular lens implantation after cataract surgery in children

PURPOSE

To report results of secondary intraocular lens implantation after cataract surgery in children.

METHODS

We reviewed clinical records for a 5-year period of patients who had cataract surgery in childhood and received a secondary intraocular lens implant. We studied indications for secondary intraocular lens placement; surgical procedures for intraocular lens implantation; preoperative and postoperative visual acuity, refractive error, and binocular status; and complications of the procedure.

RESULTS

A secondary intraocular lens was placed in 28 eyes of 25 patients who had cataract surgery in childhood. In 20 eyes, the lenses were placed in the ciliary sulcus. The other eight eyes had insufficient capsular support for an intraocular lens; in two, the intraocular lens was placed in the anterior chamber and, in six, in the posterior chamber with suture fixation to the sclera. Twenty of 28 eyes (71%) had measurable improvement in visual acuity; only one eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye; 21 (75%) were within 3.00 diopters. During follow-up, two eyes developed glaucoma. One had transient pressure elevation; one required two filtration procedures. Three patients required Nd:YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near; three demonstrated 200 seconds of arc or better stereo visual acuity.

CONCLUSION

Secondary placement of an intraocular lens in the posterior chamber appears to be a safe, effective alternative for correction of aphakia in the contact lens- or spectacles-intolerant child or young adult.

Congenital aphakia: a clinicopathologic report of three cases

BACKGROUND

Congenital aphakia is a rare condition that has been classified as primary when no lens induction of the surface ectoderm occurs and secondary when lens development takes place but later is resorbed or expelled in utero.

METHODS

The authors report the clinical and pathologic findings in three infants with congenital aphakia whose eyes were enucleated either at surgery at 11 months or at autopsy after 1 and 3 days of life.

RESULTS

Two cases classified as primary congenital aphakia had severe microphthalmos, anterior segment aplasia, or anomalous development and posterior choroidal and optic disc colobomas. One was in a case believed to be Waardenburg's recessive anophthalmia syndrome and the other had 18 trisomy. A case of secondary congenital aphakia had findings of Peter's syndrome and features suggesting rubella, which had been observed in some previous reports.

CONCLUSIONS

Primary congenital aphakia can result from a variety of teratogenic events in the first 4 weeks of embryogenesis and results in microphthalmos and severe anterior segment aplasia/dysplasia. Secondary congenital aphakia is associated with less severe ocular anomalies. The possible role of deletion or mutation involving the PAX6 gene in anterior segment anomalies and induction of lens development is discussed. In addition to chromosomal influences, in utero viral infection, particularly rubella, may play a role in some cases.

Infantile exotropia

BACKGROUND

Exotropia is uncommon in healthy children between 6 months and 1 year old.

METHODS

The charts of patients treated in our practice between January 1980 and August 1994 were reviewed for a diagnosis of infantile exotropia. All of them had an exodeviation during the first year of life. Children with neurologic defects, prematurity, trauma, craniofacial syndromes, or orbital abnormalities or ocular defects that would reduce vision were eliminated.

RESULTS

Sixty-six healthy patients with normal eyes had an exodeviation of 15 prism diopters (delta) or more that persisted through the first year of life. Fifty-four were eliminated because the diagnosis had not been confirmed by a pediatric ophthalmologist before they were 1 year old or they had not been followed for more than 4 years. The 12 remaining patients were followed for at least 4 years (mean, 7.9 years). The mean age at the first examination was 7.8 months (range, 4 to 12 months). On early evaluation, exotropia was intermittent in four and constant in eight. Three had amblyopia. Ten required surgical correction. Exotropia was corrected with one operation in six patients; four required additional procedures, mostly to correct oblique muscle overaction and dissociated vertical deviation (DVD). At the most recent visit, all 12 patients had equal visual acuity in both eyes and satisfactory ocular alignment. Five had fusion at distance and near, but only two had stereo acuity of 100 seconds of arc or better.

CONCLUSION

Infantile exotropia is rare. But, like patients with infantile esotropia, those with exotropia can be expected to have good visual acuity but unstable ocular alignment. Also, as with early-onset esotropia, although surgical intervention is usually required, high levels of binocular function develop in some patients with exotropia. Oblique muscle overaction and DVD are common, often becoming manifest by the first year of age. Unlike infantile esotropia, nystagmus is rare.

Pediatric cataracts

The treatment of an infant or child with a cataract requires a different decision process and surgical technique compared with the treatment of an adult with a cataract. The pediatric cataract literature of the past year reminds the reader that the indications for surgery and preoperative management of the pediatric cataract patient are different, that the response to surgery is different, necessitating the use of new techniques for surgery, and that complications after surgery are more common. These differences are caused by the anatomy of the pediatric eye and the susceptibility of the developing visual system to amblyopia. The literature of the past year supports with laboratory study and clinical reports the current trend toward more common use of intraocular lenses in children.

Early retinal vessel development and iris vessel dilatation as factors in retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) Cooperative Group

OBJECTIVE

To determine whether the extent of retinal vessel development present on early screening examinations for retinopathy of prematurity has prognostic value?

DESIGN

The prospectively collected data from the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity were used to compare the development of acute retinopathy of prematurity and long-term structural and visual outcomes for eyes with differing extents of retinal vessel development.

PATIENT

Study patients had eyes with the following vessel development. In zone I eyes, vessels extended from the disc less than twice the distance from the disc to the macula. In zone II eyes, vessels extended beyond zone I but not to the nasal ora serrata. Transitional eyes had vessels partly in zone I and partly in zone II.

RESULTS

The chance of developing threshold retinopathy of prematurity was inversely related to the early degree of vessel development: 54% for zone I eyes, 25% for transitional eyes, and 8% for zone II eyes. The presence of prominent iris vessels at 34 to 35 weeks of postmenstrual age was associated with increased risk for all three groups; zone I eyes almost always needed treatment (94%). The chance of having an unfavorable anatomic alteration of the posterior fundus, or poor vision at the ages of 1 year and 3 1/2 years, was also inversely related to the degree of early vessel development. Vessel development was an independently important factor even when birth weight, gestational age, and race were considered.

CONCLUSIONS

The degree of early retinal vessel development is a significant predictor of outcome from retinopathy of prematurity. Iris vessel dilatation is an important indication for greater vigilance in following these infants.

Results following secondary intraocular lens implantation in children

BACKGROUND

Placement of a secondary intraocular lens (IOL) in a child may be considered in children with congenital monocular cataracts who have had complete opacities removed early in life and who later become contact lens intolerant, in eyes that have received trauma which precluded placement of a primary IOL, and in young adults who have bilateral aphakia who become resistant to use of contact lenses or spectacles.

METHODS

Clinical records of all children in our practice who received a secondary IOL between January 1988 and December 1994 were reviewed. Indications, biometry, type of procedures, preoperative and postoperative acuity, refractive error, binocular status, and complications were studied.

RESULTS

During the 7-year period, 242 cataract operations were performed. Fifty-nine eyes received a lens implant, and 28 of these were secondary implants. There was a mean interval between the initial cataract operation and the procedure for the secondary implant of 77 months. The mean follow-up was 35 months (range, 3 to 71) for the 28 eyes that received a secondary implant. Two received anterior chamber implants. Eight eyes had insufficient capsular support for an IOL. Six implants were placed in the posterior chamber and required suture fixation to the sclera. Twenty of 28 eyes had a measurable improvement in visual acuity. Only 1 eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye, and 75% were within 3.00 diopters. During the follow-up period, 2 eyes developed glaucoma. One had a transient pressure elevation, and the second has required 2 filtration procedures. Three patients required a Nd: YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near, but only 3 patients demonstrated 200 seconds of arc or better stereo acuity.

CONCLUSION

Placement of contemporary-style, secondary intraocular lenses in children and young adults appears to provide a safe and effective alternative for correction of aphakia in children who become contact lens or spectacle-intolerant.

Penicillium marneffei infection in a patient with SLE

We describe a patient with SLE who was infected by the fungus Penicillium marneffei. She was initially misdiagnosed as having disseminated tuberculosis. The correct diagnosis was finally made by bone marrow culture and she responded to a prolonged course of amphotericin B, flucytosine and itraconazole. The clinical presentation and histology of penicilliosis are very similar to those of Mycobacterium tuberculosis. In Southeast Asia, penicilliosis should be considered as a differential diagnosis in patients with SLE who present with fever and lymphadenopathy.

A prospective, randomized, controlled comparison of retrobulbar and general anesthesia for strabismus surgery

A prospective, randomized controlled study (n = 95) was conducted to compare the morbidity and length of hospital stay associated with retrobulbar neuromuscular blockade (LA) with that associated with general anesthesia (GA) for monocular strabismus surgery in adult patients. A scoring system was developed to assess postoperative nausea and vomiting, pain, level of consciousness, oral intake, and activity while in the hospital and for the first 3 postoperative days. There was no significant difference in the postoperative nausea and vomiting associated with the two anesthetic techniques. Although patients receiving LA experienced less immediate postoperative discomfort (P < .01) and had greater levels of activity (P < .0001) while in the hospital, the discomfort and activity levels of the two groups were similar at home. The LA group was discharged from the hospital sooner (mean, 135 minutes vs 250 minutes; P < .001), allowing more efficient use of hospital resources. Both techniques provided excellent anesthesia for monocular strabismus surgery.

Risk factors for complications following pediatric epikeratoplasty

We studied the prevalence and types of complications that occurred in children treated with epikeratoplasty to identify risk factors. A review of the clinical records of 88 consecutive patients (106 eyes; 114 procedures) revealed that no complications occurred in 58 grafts (54%). Refractive complications (refractive error greater than 3.00 diopters spherical equivalent from emmetropia or astigmatism greater than 3.00 diopters) occurred in 30 eyes (28%). Medical complications occurred in 22 eyes (19%); these included epithelial defects (14 grafts), interface opacities (six grafts), graft vascularization (eight grafts), graft infection (two grafts), graft necrosis (five grafts), graft haziness (four grafts) or opacification (11 grafts), and graft dehiscence (three grafts). Eleven grafts (10%) were removed and five eyes received new grafts. Epikeratoplasty in children will be more successful if risk factors such as patient age less than one year, microcornea, corneal endothelial cell dysfunction, mental retardation, and combining the procedure with cataract surgery are avoided.

Disseminated intravascular coagulopathy associated with rifampicin

A case of subclinical disseminated intravascular coagulopathy due to antituberculosis drugs, probably rifampicin, is described. The patient also developed marked leucocytosis, a 'flu-like illness, intravascular haemolysis, and acute renal failure as part of the drug reaction.

Congenital dacryocele. A collaborative review

Fifty-four cases of congenital dacryocele from several medical centers were reviewed retrospectively. There was strong female preponderance (73%) and unilateral involvement (88%). Lacrimal sac contents could be expressed by local massage through the puncta in 21% of cases. Probing and irrigation were done under general (27.8%) or local (55.6%) anesthesia, while in other cases (16.7%), the cyst resolved before intervention. Recurrence of the dacryocele occurred in 10 patients (22%) after probing. Nasal cysts were visualized in six cases. Marsupialization of nasal cysts was necessary in four cases. In one center, after conservative therapy, 80% of cysts resolved spontaneously and 20% developed dacryocystitis. Surgical intervention is indicated in cases of dacryocystitis, cellulitis, breathing difficulty from large nasal cysts, recurrent dacryocele, and lack of its resolution after a short trial of digital massage.

Herpes zoster associated encephalitis in dialysis patients

Two patients on dialysis because of chronic renal failure who developed herpes zoster associated encephalitis are reported. Both developed overt encephalopathy despite treatment with oral acyclovir for the preceding herpes zoster eruption. The encephalopathy responded rapidly to intravenous acyclovir.

Visual results after early surgical treatment of unilateral congenital cataracts

The authors reviewed the records of 25 consecutive patients who had been operated on for unilateral congenital cataracts at 1 year of age or younger and who had been followed for a period of 5 years or longer. Excluded were patients who demonstrated retinal and optic nerve anomalies. Five eyes achieved 20/40 or better Snellen visual acuity, 5 eyes achieved 20/50 to 20/100 visual acuity, and 15 eyes had 20/200 or less visual acuity. All patients with visual acuity of 20/40 or better had cataract surgery performed before 17 weeks of age, the critical period, and surgery was scattered within this time frame. For surgery performed between 17 weeks and 1 year of age, the best achieved visual acuity in children with surgically significant unilateral congenital cataracts was between 20/50 and 20/100. There was no correlation between the age at the time of surgery and the attainment of these visual levels in this patient subset.

Management of posterior lenticonus

Posterior lenticonus is associated with progressive lens opacification. We report a series of 40 consecutive patients (41 eyes) with posterior lenticonus who were treated by three pediatric ophthalmologists between 1974 and 1988. Prior to cataract surgery, appropriate patients were treated with atropine dilatation, spectacle correction including bifocals for refractive errors, and amblyopia occlusion therapy. Indications for surgery were a measured decrease in visual acuity, the loss of a central fixation reflex, or the onset of strabismus. The age at which cataract surgery was performed ranged from 2 months to 12 years (mean 4 years, 6 months). Nineteen eyes (49%) achieved postoperative acuities in the 20/20 to 20/40 range, 7(18%) eyes achieved 20/50 to 20/100, 4 (10%) eyes achieved 20/200, and 4 (10%) eyes achieved less than 20/200. Two (5%) young patients had central, steady, and maintained visual fixation reflexes and 3 (8%) additional patients had central, steady, but not maintained reflexes. After cataract surgery and aphakic optical correction, amblyopia was present in 84% of patients and strabismus was present in 51% of patients. The patients in this study had sufficient optical distortion to produce amblyopia. Cataract removal and optical correction alone did not correct the vision; occlusion therapy for amblyopia was required. Earlier surgery may be indicated to prevent visual deprivation amblyopia in patients with posterior lenticonus.

Visual recovery in patients with optic neuritis and visual loss to no light perception

We reviewed the records of 151 patients with optic neuritis examined over an eight-year period. Of these patients, 12 developed visual acuity of no light perception during the first episode of optic neuritis in the affected eye. Eight of the 12 patients recovered visual acuity of 20/40 or better. Of these, five patients had visual acuity of 20/20 or better, one had visual acuity of 20/25, one had visual acuity of 20/30, and one had visual acuity of 20/40. Four of the 12 patients recovered peripheral visual fields but had dense central scotomas and visual acuity of less than 20/400. Dyschromatopsia persisted after visual recovery in 11 of 12 patients.

Clinical and upper gastroendoscopic features of patients with dengue virus infection

Clinical observation was made on 238 dengue fever cases during an epidemic in Taiwan from September to November 1988. Dengue virus infection type 1 was responsible for all cases. The majority of patients had acute onset of fever with abdominal pain, diarrhoea, and vomiting. Gastrointestinal haemorrhage with manifestation of haematemesis and/or melena was observed in 28 (11.8%) of our patients. The clinical gastrointestinal features in patients with a peptic ulcer history were not different from those in patients without it. There was no significant difference in incidence of gastrointestinal manifestations between premedication and non-premedication patients. Sixty-six non-premedication patients in our series were examined by gastroduodenoscopy. Haemorrhagic gastritis was the most common finding in 27 (40.9%) patients. The incidence of gastric and/or duodenal ulcerations was higher in patients with a peptic ulcer history compared with those without it (P less than 0.01). However, the incidence of upper gastrointestinal bleeding was similar between these two groups (19.2% vs 9.8%). Thrombocytopenia in patients with gastrointestinal haemorrhage was more prominent than in those without it (P less than 0.005). This implied that thrombocytopenia might be one of the predisposing factors for gastrointestinal haemorrhage.

Bilateral phakic hypermetropic epikeratoplasty for accommodative esotropia

Optical correction of high hypermetropia with glasses is the primary treatment for accommodative esotropia. These glasses are often poorly accepted by adolescents and young adults for they are cosmetically undesirable, heavy, and esotropia occurs with their removal. We report an 11 1/2-year-old, physically mature female with high hypermetropia and accommodative esotropia corrected to orthophoria with glasses who was unable to be weaned from her glasses. She became intolerant to glasses wear, refused contact lenses, and was treated successfully with bilateral phakic hypermetropic epikeratoplasty. Two years postepikeratoplasty her visual acuity is 20/40 and 20/20 uncorrected and the vision in the amblyopic right eye has remained at its maximum preoperative level. She is orthophoric at distance and has a 2 prism diopter monofixational esophoria at near without glasses. Epikeratoplasty is an option in the treatment of accommodative esotropia for patients who are past the amblyopia forming age, have a stable angle of strabismus, and who require their full hypermetropic optical correction to maintain orthophoria.

The development of an improved murine iontophoresis reactivation model for the study of HSV-1 latency

The present study reviews the development of an effective murine iontophoresis reactivation model for the study of HSV-1 latency. In a series of experiments, Balb C mice latently infected with HSV-1 McKrae strain were iontophoresed with epinephrine X 3 days (EPI X 3/ION) or 6-hydroxydopamine X 1 day followed by topical epinephrine (6-HD ION/EPI). Reactivation and recovery of latent HSV-1 was determined by daily ocular swabs, titration, and neutralization. Additional studies determined the effect of topical ocular steroids on viral recovery rate. The results demonstrated no recovery of McKrae strain in Balb C (0%) with EPI X 3/ION, and no enhancement with topical steroids. 6-HD ION/EPI demonstrated a low recovery rate in mice (8%). However, the recovery rate was significantly increased to 50% by the addition of topical steroids to form the 6-HD ION/EPI/STEROID model, a useful experimental tool. The substitution of a clinical isolate, W strain, for McKrae strain further improved the model. The results demonstrated that, following the acute infection in mice, W strain was associated with a significantly higher (P = .001) survival rate than McKrae strain (81% vs. 52%). There was no statistically significant difference between the two strains, W vs McKrae, in Balb C mice comparing keratitis, establishment of latency (by co-cultivation), spontaneous shedding rate, or induced ocular shedding following iontophoresis. The development of an effective murine iontophoresis model offers an economical method which is uniquely suited for immunological and genetic studies of HSV-1 latency.

Efficacy of glycoprotein inhibitors alone and in combination with trifluridine in the treatment of murine herpetic keratitis

The present study examined the anti-herpetic effect of the glycoprotein inhibitors, hydroxynorvaline and 2-deoxyglucose, alone and in combination with trifluridine on murine ocular herpes. Following ocular inoculation with a large dose of HSV-1 RE strain (10(6) pfu), ICR mice were treated during the acute infection with different therapeutic regimens, and their efficacy was evaluated by ocular virus titers, clinical grading of blepharo-conjunctivitis and histological evaluation of stromal keratitis and iridocyclitis. The results following a large dose HSV-1 inoculum demonstrated that trifluridine was the best single therapeutic agent. Hydroxynorvaline and 2-deoxyglucose had no effect at all. Combination therapy of the glycoprotein inhibitors with trifluridine was no better than trifluridine alone. The mouse HSV-1 keratitis model proved to be an effective, economical alternative to the rabbit model for the evaluation of new antiviral agents.

Enkephalin degradation stimulated by captopril

Changes in the rates of degradation of Met- and Leu-enkephalin by brain aminopeptidase were measured by UV absorption after high-pressure liquid chromatography. The cleavage of enkephalin paralleled the generation of tyrosine. Captopril (SQ 14,225) stimulated enzyme activity, to a greater extent with Met- than with Leu-enkephalin. Pro-His-Pro-NH2, histidine, and histamine stimulated enkephalin aminopeptidase approximately twice as much as captopril. The sulfhydryl group of captopril was not the only factor in its effect. The addition of captopril did not change the pH optimum, and it stimulated enkephalin degradation between 25 and 50 degrees C.

Degradation of melanotropin inhibiting factor by brain

Degradation of melanotropin inhibiting factor (MIF) was measured by fluorometry, using pareptide as an internal standard, following the separation of the dansyl derivatives of MIF and its metabolites by HPLc. MIF was not split by carboxypeptidases A and B, prolidase, or pyroglutamate aminopeptidase. It was hydrolyzed by leucine aminopeptidase, aminopeptidase M, and carboxypeptidase Y. Rat brain hydrolyzed 159 nmol of MIF per mg of protein per h; the activity was linear with enzyme concentration. Hydrolysis start from the N-terminal end, as shown by the appearance of proline as the first metabolite of the MIF degradation, followed by leucine, glycinamide, leucylglycine, and glycine. Activity in the rat brain regions was in the order striatum, medulla oblongata > cortex, hippocampus, midbrain > hypothalamus, cerebellum, and pituitary. The enzyme was mostly in the supernatant, with significant amounts in the myelin and synaptosomal fractions. MIF aminopeptidase could be separated from carboxypeptidase by centrifugation at 30,000 x g for 20 min and precipitation with 45--75% (NH4)2SO4. It showed pH optima in the alkaline range (8.25 and 8.75) and was inhibited by EDTA, EGTA, SQ 14,225, puromycin, bacitracin, and bestatin.