Activation of the human immunodeficiency virus promoter by UVA radiation in combination with psoralens or angelicins

The effects of mono- and bifunctional furocoumarins plus UVA radiation (PUVA and related treatments) on the human immunodeficiency virus-1 (HIV-1) promoter were studied using HeLa cells stably transfected with the chloramphenicol acetyl transferase gene under the control of the HIV-1 promoter. The experiments were performed with three psoralens (5-methoxypsoralen, 5-MOP; 8-methoxypsoralen, 8-MOP; and 4'-aminomethyl-4,8,5'-trimethylpsoralen, AMT) and four angelicins (angelicin; 4,5'-dimethylangelicin, 4,5'-DMA; 6,4'-dimethylangelicin, 6,4'-DMA; and 4,6,4'-trimethylangelicin, TMA). The drugs alone and UVA radiation alone showed no effect on the HIV promoter. However, when the cells were incubated with the furocoumarins at 0.1-40 micrograms/mL and then irradiated, the HIV promoter was activated in distinct fluence ranges, i.e. (1) no promoter activity was discernible at low fluences (e.g. at 0.1 microgram/mL of 8-MOP up to 100 kJ/m2), (2) as the fluence was increased, the promoter activity increased to reach a maximum (10-50-fold with respect to the unexposed samples), and (3) as the fluence was further increased, the promoter activity decreased. Similar (although shifted on the fluence scale) patterns were observed with either > 340-nm UVA radiation or with UVA radiation contaminated with a small amount of UVB radiation (typical for PUVA lamps). The effective fluences were inversely related to the drug concentration. Experiments with 5-MOP and 8-MOP indicated reciprocity of the drug concentration and radiation fluence. The HIV promoter response patterns were similar for monofunctional angelicins and bifunctional psoralens.(ABSTRACT TRUNCATED AT 250 WORDS)

The analysis of benefit and risk of combined pancreatic and renal transplantation versus renal transplantation alone

Currently, diabetes mellitus is the most common cause of renal failure in adults. However, combined pancreatic and renal transplantation (PRT) remains controversial when compared with renal transplantation alone (RTA) in diabetic recipients. We analyzed the results and morbidity in four age-matched groups--31 patients with Type I diabetes undergoing PRT before dialysis, 30 patients with diabetes who are dependent of dialysis undergoing PRT, 31 concurrent and historic patients with Type I diabetes undergoing RTA and 31 concurrent patients without diabetes undergoing RTA. All patients received cadaver donor organs and were managed with cyclosporine and prednisone immunosuppression with selective OKT3 induction. The four groups were comparable with respect to age, weight, gender, duration and severity of diabetes, dialysis type, number of retransplants, degree of sensitization, preservation time and matching. The groups differed with regard to duration of dialysis and period of follow-up evaluation, pretransplant blood transfusions, racial distribution and OKT3 induction therapy. PRT was associated with a greater morbidity rate as evidenced by a slightly higher incidence of rejection, infections and reoperations. The number of readmissions and hospitalization period during the first 12 months was also greater after PRT versus RTA. However, none of these differences were significant. No detrimental effect was noted on renal allograft function at one year; patient and graft survival was actually higher in the PRT groups. Quality of life was improved in nearly 90 percent of PRT recipients. Although the improved results after PRT may be attributed to selection bias, only lesser differences were noted among the four study groups. The aforementioned data suggest that appropriate patient selection can overcome the morbidity associated with PRT, resulting in excellent patient and graft survival with the potential for complete rehabilitation.

Behavioral toxicity of anticholinesterases in primates: chronic physostigmine and soman interactions

Dose rates for continuous infusion of physostigmine salicylate required to inhibit 30 and 60% of normal serum cholinesterase activity in rhesus monkeys were determined. The effects of continuous physostigmine infusion at these dose rates on the behavioral toxicity of daily repeated low-dose soman were determined not to be deleterious; in fact, they were slightly (and variably) protective.

Long-wavelength UVA radiation induces oxidative stress, cytoskeletal damage and hemolysis

We investigated the ability of the different wavelength regions of UV radiation, UVA (320-400 nm), UVB (290-320 nm) and UVC (200-290 nm), to induce hemolysis. Sheep erythrocytes were exposed to radiation from either a UVA1 (> 340 nm) sunlamp, a UVB sunlamp, or a UVC germicidal lamp. The doses used for the three wavelength regions were approximately equilethal to the survival of L5178Y murine lymphoma cells. Following exposure, negligible hemolysis was observed in the UVB- and UVC-irradiated erythrocytes, whereas a decrease in the relative cell number (RCN), indicative of hemolysis, was observed in the UVA1-exposed samples. The decrease in RCN was dependent on dose (0-1625 kJ/m2), time (0-78 h postirradiation) and cell density (10(6)-10(7) cells/mL).. Hemolysis decreased with increasing concentration of glutathione, hemoglobin or cell number, while the presence of pyruvate drastically enhanced it. Because scanning spectroscopy (200-700 nm) showed that hemoproteins and nicotinamide adenine dinucleotides were oxidized, cytoplasmic oxidative stress was implicated in the lytic mechanism. Further evidence of oxidation was obtained from electron micrographs, which revealed the formation of Heinz bodies near the plasma membrane. The data demonstrate that exposure of erythrocytes to UVA1, but not UVB or UVC, radiation causes oxidation of cytoplasmic components, which results in cytoskeletal damage and hemolysis.

A comparative analysis of results and morbidity in type I diabetics undergoing preemptive versus postdialysis combined pancreas-kidney transplantation

Although combined pancreas-kidney transplantation (PKT) has become a valid treatment option for selected type I diabetics, the timing of PKT relative to the degree of nephropathy remains controversial. We analyzed results and morbidity in 30 type I diabetics undergoing PKT after starting dialysis (PKT:D) versus 31 type I diabetics undergoing PKT prior to dialysis (PKT:ND). The two groups were similar with the respect to age, duration and severity of diabetes, gender, race, preservation time, retransplants, sensitization, HLA-matching, and CMV status. The mean preoperative serum creatinine was higher in the PKT:D group (9.9 +/- 3.4 vs. 3.9 +/- 1.9 mg/dl PKT:ND, P < 0.01). All patients were managed with quadruple immunosuppression with OKT3 induction. Actuarial patient survival is 100% (PKT:D) and 96.8% (PKT:ND). Renal and pancreas allograft survival are 97% and 93%, respectively, in both groups. The incidence of rejection, infection, operative complications, reflux pancreatitis, and total hospital days was similar in both groups. Long-term renal and pancreas allograft function and quality of life were like-wise comparable. No adverse coagulation or immunologic effects were noted in the PKT:ND group. Rehabilitation potential favored the PKT:ND group. PKT can be performed safely and effectively in the absence of uremia. In selected type I diabetics with significant nephropathy, we believe that PKT is the best treatment option and need not be considered as preemptive, especially in view of increasing waiting times and the variable progressive nature of diabetic complications.

Efficacy of physostigmine as a pretreatment for organophosphate poisoning

Continuous administration of the carbamate physostigmine, producing approximately 40% serum cholinesterase (ChE) inhibition, provides significant protection against the lethal effects of the organophosphorous nerve agent pinacolyl methylphosphonofluoridate (soman). Rats pretreated with physostigmine were also protected against the development of cholinergic symptoms and loss of body weight. Soman and physostigmine both inhibit ChE, yet animals pretreated with physostigmine exhibited less ChE inhibition in serum and brain than did animals exposed to soman alone. In addition, there did not appear to be any additive effect of presenting both anticholinesterases simultaneously. To further examine the effectiveness of physostigmine, we compared the results of this study with previously collected pyridostigmine data from our laboratory. This comparison indicates that physostigmine is more effective than pyridostigmine in protecting against the detrimental effects of soman.

Lipid status after combined pancreas-kidney transplantation and kidney transplantation alone in type I diabetes mellitus

This study was designed to compare changes in lipid status following organ transplantation between type I diabetes mellitus (DM-I) patients receiving combined pancreas-kidney transplantation (PKT) with those receiving kidney transplantation alone (KTA). A retrospective chart review was used to identify pre- and posttransplantation fasting total cholesterol (TC) and triglycerides (TG) in three groups: DM-I patients receiving KTA (DM:KTA; n = 14), DM-I patients receiving PKT (DM:PKT; n = 20), and kidney transplant recipients without DM (NDM; n = 16). The groups were matched for age, gender, weight, duration of dialysis, smoking history, and duration of diabetes mellitus. Linear regression was used to analyze differences in lipid trends over time (up to 24 months posttransplantation) and the effects of prednisone dose, cyclosporine dose, and serum creatinine. Preoperative TC was significantly lower in the DM:KTA group (P < 0.05) compared with DM:PKT or NDM. There were no significant differences in preoperative TG between the three groups. TC and TG decreased over time only in DM:PKT (P = 0.0112, P = 0.0278, respectively). TC increased and TG was unchanged over time in DM:KTA (P = 0.0003, P = 0.1103, respectively). Neither TC nor TG changed over time in NDM. Trends of TC and TG for DM:PKT were significantly different from DM:KTA (P < 0.01 for both). Trend of TC for NDM was also significantly different from DM:PKT (P = 0.0061). Prednisone dose was significantly related to TC in DM:KTA and NDM (P < 0.01) while cyclosporine dose was significantly related to TC for DM:KTA only (P = 0.0013) in the presence of time. None of the variables tested (prednisone dose, cyclosporine dose, and serum creatinine) significantly affected TG in the presence of time. In summary, TC and TG decreased over time only in DM:PKT. In contrast, TC increased while TG was unchanged in DM:KTA over the same interval (0-24 months). If these trends continue, the beneficial change in lipids in the DM:PKT group may translate into a net improvement in atherosclerosis-mediated events for diabetic patients with chronic renal failure who receive PKT compared with those who do not.

Use of cholinesterases as pretreatment drugs for the protection of rhesus monkeys against soman toxicity

Purified fetal bovine serum acetylcholinesterase (FBS AChE) and horse serum butyrylcholinesterase (BChE) were successfully used as single pretreatment drugs for the prevention of pinacolyl methylphosphonofluoridate (soman) toxicity in nonhuman primates. Eight rhesus monkeys, trained to perform Primate Equilibrium Platform (PEP) tasks, were pretreated with FBS AChE or BChE and challenged with a cumulative level of five median lethal doses (LD50) of soman. All ChE-pretreated monkeys survived the soman challenge and showed no symptoms of soman toxicity. A quantitative linear relation was observed between the soman dose and the neutralization of blood ChE. None of the four AChE-pretreated animals showed PEP task decrements, even though administration of soman irreversibly inhibited nearly all of the exogenously administered AChE. In two of four BChE-pretreated animals, a small transient PEP performance decrement occurred when the cumulative soman dose exceeded 4 LD50. Performance decrements observed under BChE protection were modest by the usual standards of organophosphorus compound toxicity. No residual or delayed performance decrements or other untoward effects were observed during 6 weeks of post-exposure testing with either ChE.

Photic maculopathy after extracapsular cataract surgery. A prospective study

Photic retinal injuries have been described after surgical exposure to the intense illumination systems of operating microscopes. The overall incidence of such injuries has been postulated at less than 10%. The authors prospectively studied 43 consecutive patients to determine the incidence of photic macular injuries during cataract surgery. Patients underwent complete ophthalmic examinations, fundus photography, and oral fluorography before and after surgery. Photic macular injuries developed in 12 of 43 eyes (28%) as a result of intraocular surgery. This incidence is much higher than previous estimates. The association with possible risk factors, cystoid macular edema, and the effect of these injuries on final visual acuity are discussed.

Photoaging effects on spectral transmittance of plastic filters

We examined the effects of ultraviolet (UV) radiation in combination with high levels of infrared (IR) radiation on the spectral transmittance of plastic filters. The biological action spectrum for damage to the human eye and skin changes dramatically in the 300-400 nm wavelength range. Cut-off filters used in this region to shape the spectrum of exposure sources are thus critical to the design of experiments which use broadband light sources. The changes in transmittance of three types of plastic filters were observed over an exposure period of 1000 h. One set of three filters was exposed mainly to UV radiation, while the other set was exposed to UV radiation plus IR radiation. Filters exposed to both UV and IR radiation showed spectral changes in their transmittance, while the filters exposed to UV only showed no measurable changes.

Indirect ophthalmoscopes: evaluation for potential hazard

The optical radiation emitted from eight indirect ophthalmoscopes was measured. The levels were compared with the threshold limit values (TLVs) published by the American Conference of Governmental Industrial Hygienists. Many tested instruments were found to emit unnecessarily high levels ofultraviolet and infrared radiation in addition to visible light. The levels of optical radiation emitted from most of the ophthalmoscopes were below the applicable TLVs. Nevertheless, suitable blocking filters can reduce the emission of ultraviolet and infrared radiation. Use of the ophthalmoscopes at the lowest possible power setting and the shortest possible exposure time would further minimize patient exposure.

The impact of alpha-adrenergic stimulation on umbilical blood flow

This study evaluated the effects of intranasal phenylephrine, an alpha-adrenergic agonist used for respiratory congestion, on uteroplacental blood flow. Twelve subjects were recruited from the Women's Clinic. Inclusion criteria were age greater than 18 years, singleton gestation, absence of medical illness and gestational age of 22-38 weeks. Phenylephrine (0.2 ml of 1% aq. solution) was applied to each nostril. Maternal blood pressure and pulse, umbilical artery velocimetry, and fetal heart rate were recorded prior to drug administration and at 5, 15, 30, 45 and 60 min after administration. There were no significant changes in maternal pulse, blood pressure or fetal heart rate. All subjects had normal baseline umbilical artery Doppler systolic/diastolic ratios. Eleven of 12 subjects demonstrated an elevation of the systolic/diastolic ratio consistent with vasoconstriction following administration. This elevation reached statistical significance at 30 min. Significant individual variation existed with regards to timing of maximal excursion of the systolic/diastolic ratio. The mean maximal change of the systolic/diastolic ratio was 1.57 +/- 1.25 (p < 0.001) ranging from -0.53 to 4.11. The use of over-the-counter alpha-adrenergic agents may result in decreased umbilical artery flow velocities. In high-risk pregnancies these medications may be contraindicated.

Reliability problems associated with the modified Schöber technique for true lumbar flexion measurement

The modified Schöber technique, a method for assessing lumbar spine flexion, was subjected to an analysis of reliability. Fifty normal subjects (21 men, 29 women) were evaluated for lumbar flexion mobility using a blind inter-rater "worst case" protocol. Simultaneously, other sources of error affecting test reliability, such as presence of dimples of Venus, relationship of skin distraction to movement of underlying structures, and upper level of Schöber skin landmarks were also considered. Analysis suggested that systematic error can be introduced that adversely affects inter-rater reliability (r = 0.71). Moreover, skin landmarks are inconsistently present, being completely absent in 26% of cases. Skin tends to distract even over completely immobile bony structures (eg, the sacrum), whereas, on average, only 3.5 of the 6 spinal segments (T12-S1) are included in the Schöber technique for purported measurement of "lumbar spine flexion." The utility of this method is questioned on both scientific and clinical grounds.

Lipid status after pancreas-kidney transplantation

OBJECTIVE

This study was performed to determine the net effects of euglycemia, resolution of renal failure, immunosuppressant drugs, and hyperinsulinemia on fasting lipid profiles of patients with renal failure and insulin-dependent diabetes mellitus (IDDM) after combined pancreas-kidney transplantation (PKT).

RESEARCH DESIGN AND METHODS

Thirty subjects with IDDM received PKT between April 1989 and October 1990, and all were studied. Mean +/- SE age was 35.2 +/- 1.3 yr; 19 recipients were men, and 11 were women. All had a functioning pancreatic allograft post-PKT. Fasting lipid profiles including total cholesterol (C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-chol), and C/HDL-chol were compared before and after PKT (38-555 days divided into groups: preoperation and 0-2, 3-8, and 9-19 mo).

RESULTS

Significant hyperlipidemia was observed preoperatively (means +/- SE): C, 5.92 +/- 0.27 mM; HDL-chol, 1.07 +/- 0.09 mM; TG, 5.85 +/- 0.56 mM; and C/HDL-chol, 6.49 +/- 0.83. All lipids and C/HDL-chol dropped immediately after PKT (0-2 mo vs. preoperation, all P less than 0.01, except HDL-chol). After this immediate postoperative period, C, HDL-chol, and TG stabilized at new concentrations. C (5.44 +/- 0.22 mM) and TG (4.54 +/- 0.48 mM) levels were less than preoperation (not statistically significant and P less than 0.05, respectively). HDL-chol was greater than preoperative values (1.29 +/- 0.06 mM, P less than 0.05). C/HDL-chol dropped after PKT (0-2 mo, 4.85 +/- 0.18, P less than 0.01) and continued to decrease throughout the observation period (3-8 mo, 4.42 +/- 0.23; 9-19 mo, 4.23 +/- 0.23; both P less than 0.01 vs. preoperation). There was no statistical difference between lipid concentrations in male and female subjects.

CONCLUSIONS

The lipid status of subjects with IDDM and renal failure was abnormal before PKT and once lipid concentrations stabilized after PKT (greater than 2 mo), HDL-chol was higher and TG and C/HDL-chol levels were significantly lower than preoperative values. If these changes are sustained, risk of future cardiovascular disease in this group of patients might be significantly reduced.

Generally recognized as safe (GRAS) evaluation of 4-hexylresorcinol for use as a processing aid for prevention of melanosis in shrimp

4-Hexylresorcinol (C12H18O2) is proposed for use as a processing aid for prevention of melanosis ("black spot") in shrimp and as an alternative to the currently approved sulfites. A safety evaluation was conducted to affirm, based upon scientific procedures, the generally recognized as safe ("GRAS") status of 4-hexylresorcinol for proposed use. The GRAS safety evaluation compiled, reviewed, and analyzed data on the following areas: chemical identity, analytical methodology, historical and proposed uses, functionality, and safety. The publicly available safety data on 4-hexylresorcinol cover a broad range of potential toxicity concerns including acute and subacute toxicity, subchronic toxicity, carcinogenicity, mutagenicity, and allergenicity. These studies, along with the aforementioned data, demonstrate that 4-hexylresorcinol presents no risk of toxicity at the levels proposed for treatment of shrimp, and the use of 4-hexylresorcinol as a processing aid to prevent melanosis in shrimp is GRAS.

Differential inactivation of surrogate viruses with merocyanine 540

Bacteriophages may be useful as surrogates for animal viruses when the virucidal properties of different photosensitizing compounds are initially investigated. We studied photoinactivation of four bacteriophages, phi X174, T7, PRD1, and phi 6, by the dye merocyanine 540 (MC540) (15 micrograms/mL). Merocyanine 540 (MC540) should be most effective with lipid-containing viruses, since it is primarily lipophilic (but also binds to proteins). Two of the phages, PRD1 and phi 6 contain lipid, with only phi 6 having an external lipoprotein envelope. Filtered radiation (450-600 nm) from a 750 W projector was used at 16-100 W/m2. The survival curves of the different viruses clearly demonstrated different levels of sensitivity to photoinactivation by MC540, with phi 6 (Do = 1.5 kJ/m2) being the most sensitive, followed by T7 (21-fold less sensitive). While both PRD1 and phi 6 have lipid components, only phi 6 was photoinactivated by MC540. Thus the internal lipid components of PRD1 were not sufficient to allow photoinactivation by this dye, at fluences up to 300 kJ/m2. For comparison, we also photoinactivated Herpes simplex virus (Do = 0.053 kJ/m2) and found it to be 28-fold more sensitive than phi 6 to photoinactivation by the same concentration of MC540. Thus phi 6 may be used as a surrogate for enveloped human viruses for photoinactivation by lipophilic dyes, but the results may only be useful qualitatively.

Differential sensitivity of CNS regions to acetylcholinesterase inhibition following chronic low-dose soman treatment in the rat

Several discrete brain regions were analyzed for regional brain sensitivity to acetylcholinesterase (AChE) inhibition following administration of repeated low-dose soman (39 micrograms/kg, SC; once daily for 5 days). The same brain regions were also assayed on days 3 through 7 after the last injection of soman, to examine possible recovery of AChE. The observed regional brain sensitivity to AChE inhibition can be described in the following order: frontal cortex = piriform cortex greater than hippocampus = cerebellum = thalamus greater than striatum = hypothalamus. Most brain areas showed only a small recovery from this inhibition through the seventh day following the last soman injection. The progressive nature of the AChE inhibition during the week of soman administration and the failure to find a significant interaction between injection and day indicates that tolerance to soman exposure did not develop in this paradigm. The protocol described here appears to provide a useful method to study prophylactic measures for low-dose repeated soman exposure and evaluation of differential CNS inhibition and recovery from AChE inhibition.

The role of platelets in the reflex tachypnoeic response to miliary pulmonary embolism in anaesthetized rabbits

Experiments were performed upon twenty-eight male Californian rabbits anaesthetized with sodium pentobarbitone and breathing room air. Successive injections of glass bead emboli (diameter 125 microns) caused an increase in respiratory rate, and decreases in tidal volume (tachypnoeic response) and platelet count. The tachypnoeic response was not observed in rabbits that had been rendered thrombocytopaenic by platelet antiserum. Induction of thrombocytopaenia by antiserum was accompanied by tachypnoea which was not significantly different (P greater than 0.05) from the response to emboli. The tachypnoeic response to antiserum, like that to emboli, was prevented by bilateral cervical vagotomy. Pre-treatment with aspirin (5 mg/kg), which inhibits the platelet-release reaction, also prevented the tachypnoeic response to both emboli and antiserum, although it did not prevent the fall in platelet count which following injection of antiserum. These data support the hypothesis that the post-embolic reflex tachypnoea is platelet dependent and may be secondary to the platelet-release reaction.

Acid-induced esophagobronchial-cardiac reflexes in humans

Esophagobronchial reflexes have been demonstrated in both the cat and dog models. In order to determine if these reflexes are present in humans and if they are vagally mediated, a prospective sequential study was initiated. One hundred thirty-six individuals referred for esophageal manometric measurements were studied. Measurements of airway flow, arterial oxygen saturation, and pulse rate were performed before and after intraesophageal infusion of sterile water, normal saline solution, and 0.1 N hydrochloric acid. Highly significant reductions in heart rate, airway flow, and arterial oxygen saturation were noted after infusion of normal saline and 0.1 N hydrochloric acid compared with baseline water infusion (P less than 0.001). Graded responses were noted with heart rate: the more acidic the solution infused, the larger the decrement of heart rate. Atropine abolished postsaline/acid decrements of airway flow, arterial oxygen saturation, and heart rate. It is concluded that acid-induced, vagally mediated esophagobronchial reflexes are present in humans.

Recovery of kiwifruit vines from transient waterlogging of the root system

The extent to which kiwifruit vines (Actinidia deliciosa var. deliciosa) recovered from transient waterlogging of the root system was determined under controlled conditions. Vines were waterlogged for periods varying from 1 to 7 days. The effects of decreasing concentrations of oxygen in the root zone on growth of the vine were rapid with substantial reductions occurring after being exposed to oxygen concentrations in the surrounding water of less than 0.125 mmol l¹ for as little as 1 day. There was no evidence of recovery of growth once aeration was restored to the roots, except for the appearance of new roots at the base of the stems of vines that had been waterlogged for less than 5 days. The quantity of new roots grown was inversely related to the time of waterlogging. Although new roots were also found on the control vines, the quantities involved were very much less than for the vines stressed for up to 4 days. No new roots were found for vines waterlogged for more than 4 days. The substantial loss of dry weight of roots of vines waterlogged for more than 3 days was due in part to a lack of growth and to a physical loss of root tissue. The loss of tissue resulted from the detachment of the cortex from the central stele through the dissolution of an entire layer of cortical cells which, in the control vines, were filled with starch. A microscopic examination of the cells of the root from waterlogged vines showed the cortical cells to be generally distorted with much of the intercellular material missing. The closure of the stomata within 2-3 h of the roots being waterlogged and the rapid desiccation of the leaves that followed the closure, was consistent with earlier findings with kiwifruit vines. Some recovery of stomata activity occurred for vines that had been waterlogged for less than 4 days once the oxygen supply to the root was restored. For vines that had their roots submerged for only 1 day, stomatal activity was fully restored 3 days after the vines were removed from the water. In contrast, there was no recovery of stomatal activity for vines that had been waterlogged for more than 3 days. A feature of stomatal behaviour that was not related to the effects of oxygen stress was the cyclic pattern which developed. Each cycle repeated itself every 4-6 days and consisted of a period of high stomatal conductance followed by a sharp decline to a much lower level. A highly significant negative relationship was found between the level of photosynthetically active radiation and stomatal behaviour. It was concluded that the speed with which the roots die and the associated damage to the leaves under anoxic conditions greatly limits the ability of kiwifruit vines to resume growth once oxygen supply to the root has been restored.

Retinal injury induced by near-ultraviolet radiation in aphakic and pseudophakic monkey eyes. A preliminary report

The effect of repeated exposures to low-intensity, near-ultraviolet (UV) radiation on the retinas of phakic, aphakic, and pseudophakic monkey eyes was studied. Ten eyes (4 aphakic eyes, 3 pseudophakic eyes, and 3 normal phakic eyes) of five rhesus monkeys were used. The near-UV radiation was generated by a high-pressure mercury vapor lamp with a total radiance of 14.43 mW/cm2/sr. Exposure regimens were 5 minutes a day for 10 days, 15 minutes a day for 5 days, or 60 minutes a day for 5 days. The retinas of aphakic and pseudophakic eyes were exposed to a daily dose of more than 0.97 J/cm2, or a total dose of more than 4.9 J/cm2 in 5 days at a retinal irradiance of more than 1.0 mW/cm2. Three of four aphakic eyes and one of three pseudophakic eyes showed clinical and pathologic retinal lesions after radiation. None of the three phakic eyes was damaged. The retinal lesions showed mild opalescent thickening ophthalmoscopically and retinal pigment epithelial staining by fluorescein angiography. Histopathologically, the retinal pigment epithelium was the site of primary injury by near-UV radiation.

Simultaneous assay of felbamate plus carbamazepine, phenytoin, and their metabolites by liquid chromatography with mobile phase optimization

Felbamate is an investigational antiepileptic drug (AED) in clinical trials. A high-performance liquid chromatographic method for the simultaneous analysis of felbamate, phenytoin (PHT), 5-(p-hydroxyphenyl)-5-phenylhydantoin, carbamazepine (CBZ), carbamazepine-10,11-epoxide, and carbamazepine-10,11-diol in serum was developed by a mobile phase optimization technique. Capacity factors for the compounds of interest and 12 other AEDs and metabolites were determined with mixtures of methanol, acetonitrile, or tetrahydrofuran and a 0.01 M ammonium phosphate buffer, pH 6.5, on a reversed-phase C8 column. An optimized mobile phase composition was determined that could separate the compounds of interest and three internal standards in less than 15 min. Serum was extracted with CH2Cl2/ethyl acetate (2:1) after addition of three internal standards. The method was validated for within-day and between-day precision and accuracy for the six compounds. Coefficients of variation were generally less than 10% at all concentrations and less than 5% in the typical therapeutic range for each compound. The lower limit of detection was estimated at 0.2 micrograms/ml for CBZ and its metabolites and 0.5 micrograms/ml for felbamate and PHT. For felbamate, the lowest point on the standard curve was 1.88 micrograms/ml with a between-day variability of 10.3%. The assay was used to determine the serum concentrations of PHT and CBZ and its metabolites in a subject before, during, and after felbamate therapy.

Problems associated with the establishment of maximum nutrient limits in infant formula

Because each increase in personal security is accompanied by a small but measurable decrease in individual liberty, congress and the American people have been reluctant to provide to the regulatory agencies authority beyond that which they believe is the minimum necessary to avoid a crisis. For government to act in any area involving nutrient fortification of foods requires an acceptable database demonstrating a health hazard. The requirements of current law demand that new formulas be investigated by appropriate clinical studies but do not grant the FDA clear authority to establish maximum limits for nutrients in infant formulas. Except when an unquestionable hazard can be demonstrated, there are important barriers to governmental action in this area. Without a clearly defined, scientifically acceptable database, without consensus in the scientific and professional community, and without public support for action to be taken in this area, the establishment of maximum limits for many nutrients will be extremely difficult.

Prediction of fertility of bovine semen: Preliminary studies with the hamster egg penetration test

The ability of liposome-treated fresh and frozen spermatozoa from two bulls to interact with zona-free hamster oocytes was examined to show whether the in vitro test results would correspond with in vivo fertility as indicated by the 60 to 90 d nonreturn to service rates which, using frozen semen, were 77 and 59%, respectively. The motility of spermatozoa in washed suspensions was also rated. Hamster test results were obtained using three ejaculates from each bull both as fresh and frozen semen. The results with frozen semen corresponded with fertility. The averages of three hamster tests for oocyte penetration rates and mean number of spermatozoa per penetrated oocyte comparing spermatozoa from the bull with the higher fertility with spermatozoa from the bull with the lower fertility were 91% and 2.7 versus 56% and 1.4, respectively. Spermatozoa washed from frozen semen from the bull with the higher fertility interacted with hamster oocytes at the higher rate even when sperm motility was rated the same for both bulls. By contrast, fresh spermatozoa from the lower fertility bull interacted with hamster oocytes at a higher rate than spermatozoa from the higher fertility bull in six tests, comparing six ejaculates of fresh semen from both bulls. Comparing the higher fertility bull with the lower fertility bull, the average of six tests for oocyte penetration rates and mean number of spermatozoa per penetrated oocyte were 60% and 1.6 versus 89% and 3.0, respectively. This suggests that this hamster test cannot be used with fresh semen to predict relative levels of fertility of frozen semen. Also, the subjective rating of sperm motility did not correspond with the in vitro oocyte penetrating ability of the spermatozoa.

Cell proliferation in chick oral membrane lags behind that of adjacent epithelia at the time of rupture

Radioautographic analysis showed that ectoderm and endoderm cells in chick oral membrane continued to label with tritiated thymidine through the period of rupture, but their frequency of labeling was significantly lower than those of adjacent epithelia. Frequency of labeling increased in adjacent ectoderm and endoderm, while oral membrane rates remained relatively low, suggesting that growth in the membrane lags relative to adjacent epithelia. Relatively greater proliferation in adjacent epithelia could generate tension and pull apart the thinned oral membrane. Differentials in rates of cell proliferation, when considered along with knowledge of cellular rearrangements following changes in basal lamina and matrical components, suggest that differential growth is an important force in rupture of the avian oral membrane.

Saccharin

Saccharin, a nonnutritive sweetener discovered in 1879, has been the subject of controversy concerning its effect on public health on several occasions during this century. Over this period, the substance has come to be regarded as a useful commodity in the dietary management of diabetes mellitus. We review the historical and scientific background on the subject and propose a new approach in making public-health decisions on unique foods that serve a special dietary purpose.

Inhibition of sexual reflexes by lumbosacral injection of a GABAB agonist in the male rat

The effects of gamma-aminobutyric acid (GABA) agonists on penile reflexes were investigated. An intrathecal injection of baclofen (0.2, 0.4, or 0.8 microgram), a GABAB receptor agonist, into the subarachnoid space of the lumbosacral spinal cord (L5-S1), resulted in a dose-related decrease in the number of animals responding in a penile reflex test. Doses of 0.2 and 0.4 microgram of baclofen decreased the number of erections; 0.4 microgram also increased the latency to the first glans erection. The highest dose of baclofen (0.8 microgram) completely inhibited penile responses in these tests. None of these doses, however, prevented rats from copulating to ejaculation. Antecedent ejaculation, which facilitated the onset of penile reflexes in saline controls, also blocked the inhibitory effects on penile responses by the lower doses (0.2 and 0.4 microgram) of baclofen, but was ineffective in animals treated with 0.8 microgram baclofen. In contrast to the inhibitory effects of baclofen in the lumbosacral cord, an intrathecal injection of baclofen (0.8 microgram) at thoracic segments (T8-T10) did not affect penile erections elicited following an ejaculation. The role of spinal GABAA receptors in sexual reflexes was assessed by intrathecal injection of a GABAA agonist. THIP (0.5.1. or 2 micrograms), onto the lumbosacral cord. Only at the largest dose of THIP were slight inhibitory effects on penile reflexes observed. Together, these data indicate that stimulation of GABAB receptors in the lumbosacral spinal cord inhibits erectile mechanisms ex copula.

Variables associated with ultraviolet transmittance measurements of intraocular lenses

We measured the spectral transmittance of 12 intraocular lenses with a spectroradiometer system that uses an integrating sphere input. We evaluated both low- and high-power lenses and varied the input aperture size between 1, 3, and 5 mm. These variations caused a significant difference in the transmittance characteristics of the intraocular lenses. Most significantly, the transmittance of the low-power model was two to six times greater than that of the high-power model in the cutoff region. The larger aperture resulted in, at most, a factor of two difference in transmittance. This effect was observed in intraocular lenses labeled both ultraviolet-absorbing and nonultraviolet-absorbing.

Changes in vascular and metabolic reactivity as indices of ischaemia in the penumbra

The reactivities of cerebral cortical blood flow (hydrogen clearance) and of compensated NADH fluorescence to local cortical electrical stimulation were examined on the marginal gyrus before and after transorbital occlusion of the middle cerebral artery in cats. Prestimulus cerebral blood flow (CBF) was 38.2 +/- 12.9 (SD) ml 100 g-1 min-1 and fell to 19.8 +/- 11.1 following occlusion (p less than 0.02). Peak hydrogen clearance rate (percent increase above prestimulus clearance) was 81.6 +/- 53.6 and fell to 19.9 +/- 29.8 after middle cerebral artery occlusion (p less than 0.01). Steady-state NADH fluorescence rose from 33.5 +/- 10.7 to 40.5 +/- 17.6% full-scale deflection following MCAO (p less than 0.01). Latency from stimulus to maximal fluorescence depression in response to cortical stimulation increased from 12.2 +/- 8.2 to 22.1 +/- 11.9 s (p less than 0.01). Hyperaemic responses at anteromedial sites on the marginal gyrus significantly exceeded those at posterolateral sites. The results are interpreted as indicating early ischaemic metabolic change; however, the presence of residual vasodilator responses to stimulation suggests that flow reduction and early ischaemic change in the territory studied are not simply due to inadequate collateral input, but may also reflect deafferentation or functional suppression. The possible significance of diminished vascular reactivity in the penumbra as a cause of increased vulnerability to extracellular release of excitatory amino acids is discussed.

Chemiluminescence immunoassay for progesterone in plasma incorporating acridinium ester labelled antigen

A sensitive, solid-phase chemiluminescence immunoassay suitable for determining progesterone concentrations in plasma has been developed. The solid-phase antiserum was prepared by coupling a monoclonal progesterone-antibody, raised against a progesterone-11 alpha-hemisuccinyl/bovine serum albumin conjugate, to cyanogen bromide activated cellulose. An 11 alpha-progesteryl-2-carboxymethyltyramine-4-(10-methyl)-a cri dinium-9-carboxylate conjugate was used as the chemiluminescent label. The assay had a lower limit of sensitivity of 3 pg/assay tube and satisfied accepted validation criteria. Progesterone concentrations determined by chemiluminescence assay were in good agreement not only with a radioimmunoassay in routine use but also with a gas chromatography-mass spectrometry procedure.

Computed tomography of the kidneys in a patient with methoxyflurane abuse

Methoxyflurane, a general anesthetic, is a known nephrotoxin. A case is presented that demonstrated diffuse, bilateral renal cortical calcification on CT secondary to repeated methoxyflurane inhalation.

The 1990 National Nutrition Objectives: lessons for the future

The 1990 objectives are a first attempt to establish quantified goals in public health nutrition. Lessons from this experience can benefit future efforts. Apparent problems related, for example, to data, methodology, feasibility, and clarity have hindered the implementation and monitoring of progress on several goals. A major step toward improvement is the development of standard criteria for evaluating proposed objectives. Dietitians and nutritionists have a special interest and responsibility in developing the National Nutrition Objectives for the Year 2000. They also have special opportunities for integrating current and future nutrition objectives into programs at the state and local levels.

Sudden infant death in service families

A study of all the cot deaths in infancy which occurred in Service families in British Forces Germany (BFG) from 1981-4 was undertaken in order to ascertain the frequency of these tragedies. The total number of deaths was ninety-seven and in sixty cases no cause of death was found at post mortem. The incidence in the Service community was calculated so that comparison could be made with the civilian population of England and Wales. The results of the study indicated that cot deaths occurred relatively more frequently in the Service population even allowing for socio-economic differences between the two groups. However, postneonatal deaths from causes other than cot death occurred less often in BFG. Cot deaths are therefore the cause of the higher postneonatal mortality rates in the Service community and they constitute an important target for preventive medicine. The measures which have been taken in BFG in recent years to reduce the number of cot deaths are discussed in this paper together with some further ideas which might help to solve this distressing problem.

Comparison of acid phosphatase ACP1 variants by isoelectric focusing and conventional electrophoresis: identification of three new alleles, ACP1*N, ACP1*P and ACP1*S

Three new alleles of human red cell acid phosphatase (ACP1) have been identified by comparison with previously reported variants using three different electrophoretic techniques. Family data are available on all the variants and show genetic transmission of the rare alleles ACP1*N, ACP1*P and ACP1*S. Further evidence of a rare allele demonstrating reversed 'A' activity is also described. The report documents the need to use several electrophoretic techniques to characterize new or rare variants.

The effects of etomidate in the cat middle cerebral artery occlusion model of brain ischaemia. An experimental study

The effects of etomidate on focal cerebral ischaemia following transorbital occlusion of the cat middle cerebral artery were investigated. Etomidate had no effect on CBF before or after onset of ischaemia by comparison with controls, but caused a greater fall in CBF in cats with high preocclusion or initial ischaemic CBF than in those in which CBF was lower. There were more sustained rises in Kp on SG. The established flow threshold for water accumulation was lost; more gyri with CBF above and fewer gyri with CBF below the flow threshold accumulated water. The relationship between mean occlusion CBF and in vitro GABA uptake was lost; uptakes from MG were lower and from SG and EG higher than expected. In the ischaemic penumbra there was a trend towards reduction in CBF, disruption of ion homeostasis and cerebral oedema formation, whilst in areas of lower flow there was some recovery of GABA uptake and less cerebral oedema following administration of etomidate.