Photodynamic therapy of the ciliary body with tin ethyl etiopurpurin and tin octaethyl benzochlorin in pigmented rabbits

BACKGROUND AND OBJECTIVES

The authors used a pigmented rabbit model to investigate two photosensitizers, tin ethyl etiopurpurin (SnET2) and tin octaethyl benzochlorin (BNZ 203), to determine their potential for creating ciliary body injuries during photodynamic therapy (PDT).

MATERIALS AND METHODS

The biodistribution of SnET2 (n = 10) and BNZ 203 (n = 9) was studied by fluorescence microscopy using a low light detection system, based on charged-coupled device photography, with digital image processing at 1 and 24 hours after injection. PDT with SnET2 (n = 8; 664 +/- 7-nm light; 75 mW/cm2; 50 or 100 J/cm2; 1-mm spot size) and BNZ 203 (n = 6; 689 nm; 75 mW/cm2; 50 or 100 J/cm2; 1-mm spot size) was performed at 24 hours post-injection. The control subjects for SnET2 (n = 5) and BNZ 203 (n = 3) were given a maximal light dose (100 J/cm2).

RESULTS

Both photosensitizers demonstrated an intravascular distribution at 1 hour that shifted to a ciliary body distribution at 24 hours (SnET2 much greater than BNZ 203). In addition, the SnET2 demonstrated suborgan localization to the nonpigmented ciliary body epithelium. Both photosensitizing agents were able to produce selective injury to the rabbit ciliary body (SnET2 much greater than BNZ 203), with evidence of a small component of thermal damage (SnET2 greater than BNZ 203).

CONCLUSIONS

PDT with SnET2 or BNZ 203 can produce selective injury to the pigmented rabbit ciliary body. The nonpigmented ciliary body epithelium exhibits selective retention of SnET2. This finding warrants further investigation.

Structure--activity studies for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid receptors: acidic hydroxyphenylalanines

Antagonists of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid (AMPA) receptors may have therapeutic potential as psychotropic agents. A series of mononitro- and dinitro-2- and 3-hydroxyphenylalanines was prepared, and their activity compared with willardiine, 5-nitrowillardiine, AMPA, and 2,4,5-trihydroxyphenylalanine (6-hydroxydopa) as inhibitors of specific [3H]AMPA and [3H]kainate binding in rat brain homogenates. The most active compounds were highly acidic (pKa 3-4), namely, 2-hydroxy-3,5-dinitro-DL-phenylalanine (13; [3H]AMPA IC50 approximately equal to 25 microM) and 3-hydroxy-2,4-dinitro-DL-phenylalanine (19; [3H]AMPA IC50 approximately equal to 5 microM). Two other dinitro-3-hydroxyphenylalanines, and 3,5-dinitro-DL-tyrosine, were considerably less active. Various mononitrohydroxyphenylalanines, which are less acidic, were also less active or inactive, and 2- and 3-hydroxyphenylalanine (o- and m-tyrosine) were inactive. Compounds 13 and 19, DL-willardiine (pKa 9.3, [3H]AMPA IC50 = 2 microM), and 5-nitro-DL-willardiine (pKa 6.4, [3H]AMPA IC50 = 0.2 microM) displayed AMPA >> kainate selectivity in binding studies. Compound 19 was an AMPA-like agonist, but 13 was an antagonist in an AMPA-evoked norepinephrine release assay in rat hippocampal nerve endings. Also, compound 13 injected into the rat ventral pallidum antagonized the locomotor activity elicited by systemic amphetamine.

Intraoperative arthrography and the Ilizarov technique. Role in the correction of paediatric deformity and leg lengthening

We performed intraoperative arthrography of the knee in 12 children with congenital short femur, Blount's disease or Ollier's disease in whom the Ilizarov technique was used for correction of deformity, leg lengthening or both. In each case, arthrography revealed a joint surface considerably different from that assumed from plain radiographs, and resulted in a change in the placement of our reference wires before application of the frame. This gave significant improvement in the mechanical axis obtained at the time of removal of the frame. The technique is safe, cheap and easy to perform. It is a useful adjunct to the application of the Ilizarov frame when used for complex lengthening and correction of deformity in the leg.

Photodynamic therapy for antifibrosis in a rabbit model of filtration surgery

BACKGROUND AND OBJECTIVE

The purpose of this pilot study was to investigate the use of photodynamic therapy (PDT) using tin ethyl etiopurpurin (SnET2) as an adjunctive antifibrotic therapy for filtering surgery in a rabbit model.

MATERIALS AND METHODS

The pharmacokinetics of SnET2 were established by intravenous (1 mg/kg) and subconjunctival (25, 50, or 75 micrograms) injections and compared with controls. Intravenous and subconjunctival SnET2 injections were given prior to posterior lip sclerectomies followed by postoperative laser irradiation (664 +/- 7 nm; 100 mW/cm2; 30 J/cm2). Antifibrotic efficacy was established by clinical response and histologic examination.

RESULTS

After subconjunctival injections, large areas of avascular conjunctiva were produced and filtering bleb survival was prolonged. No effect was found for intravenously administered photosensitizer followed by light irradiation.

CONCLUSIONS

PDT may be an alternative antifibrotic therapy for filtration surgery that does not use chemotherapeutic agents or ionizing radiation. Multiple parameters (light, drug dose, irradiation area) may be manipulated to improve predictability of the antifibrotic effect.

Improved membrane isolation in the purification of beta 2-adrenoceptors from transgenic Escherichia coli

beta 2-Adrenoceptors (beta 2-AR) have been purified from many mammalian tissues. Unfortunately, other beta-AR subtypes expressed in the same cells are usually copurified, contaminating the preparation and interfering with subsequent investigations such as receptor characterization, ligand binding studies, immunoprecipitation, or development of anti-receptor antibodies. The advent of molecular biology techniques has facilitated the expression of beta 2-AR in cells in which no other similar molecules are present; thus, receptor purification has been simplified. beta 2-AR expressed in Escherichia coli provides a convenient source of receptor without the need for specialized culture facilities required for eukaryotic cells. The greater complexity of the gram-negative cell wall structure, however, complicates the purification of membrane-bound receptor from this source. In this report, we describe a reliable method for the partial purification of membrane-bound beta 2-AR from transgenic E. coli. Spheroplast formation followed by cell disruption and a carbonate wash procedure provided beta 2-AR bound to bacterial inner membrane in high yield.

Leg lengthening and bone transport in children

It is now possible to reliably lengthen limbs for inequality or short stature by distraction osteogenesis using external fixators. Similar techniques offer new methods of treating infected fractures and non-unions and correcting soft tissue contractures and bony deformities. This article outlines the techniques and indications for leg lengthening and bone transport.

Displaced stress fracture of the femoral neck in an active amenorrhoeic adolescent

Female athletes in endurance sports are at risk of osteoporosis which predisposes them to femoral neck stress fractures. These require early diagnosis and treatment to avoid catastrophic consequences.

Actions of an IGF-I-enhancing antibody on IGF-I pharmacokinetics and tissue distribution: increased IGF-I bioavailability

We have previously demonstrated that a specific anti-IGF-I antibody will enhance the growth-promoting activity of IGF-I in vivo (Stewart et al. 1993). Since the antibody had a modest affinity for IGF-I we suggested that the antiserum might protect IGF-I from degradation whilst maintaining it in a bioavailable form. The aim of this investigation was to test that hypothesis by determining the plasma clearance and tissue distribution of tracer IGF-I in the presence of the enhancing anti-IGF-I immunoglobulin (anti-IGF-I Ig) or non-immune immunoglobulin (NI Ig). Dwarf rats were treated with saline, NI Ig or anti-IGF-I Ig for 4 days. On day 4, 125I-IGF-I (1.6 x 10(7) c.p.m.) was injected into the jugular vein and blood sampled over the next 330 min when the rats were killed: samples of liver, kidney and skeletal muscle were quickly dissected out. Mean plasma trichloroacetic acid (TCA)-precipitable 125I-IGF-I was always significantly greater (P < 0.001 for each time point) from anti-IGF-I Ig rats versus the NI Ig or saline groups (which exhibited practically identical decay curves), implying increased binding capacity for IGF-I in the anti-IGF-I Ig rats. Pharmacokinetic parameters were calculated by resolution of the decay curves using a two-phase model. The total clearance rate of 125I-IGF-I was significantly decreased (P < 0.001) by almost twofold in the anti-IGF-I versus the two control groups, consistent with the increased binding capacity in the anti-IGF Ig rats. The half-lives of the faster-decaying phase were not significantly different between treatment groups but, surprisingly, that for the slower-decaying phase was significantly decreased (P < 0.001) in the anti-IGF-I Ig rats versus the two control groups; this may reflect the low affinity of the anti-IGF-I Ig for IGF-I and its enhancing properties. The degradation of 125I-IGF-I was significantly decreased in animals receiving the anti-IGF-I Ig. In support of this, kidney TCA-precipitable radioactivity (c.p.m.) was seven-fold less (P < 0.001) in the anti-IGF-I Ig groups versus the controls, indicative of reduced excretion. Liver TCA-precipitable radioactivity was increased (P < 0.001) in the anti-IGF-I Ig rats, probably due to reticuloendothelial clearance of non-self antibodies: skeletal muscle TCA-precipitable radioactivity tended to increase in the anti-IGF-I Ig group versus the controls which might indicate increased targeting of IGF-I to muscle. Size exclusion chromatography of plasma 15 and 120 min after administration of 125I-IGF-I demonstrated a broad peak of radioactivity with a molecular mass of 150-300 kDa in the anti-IGF-I Ig-treated rats, which was responsible for more than 90% of the eluted radioactivity. This suggests that: (1) 125I-IGF-I was bound to the anti-IGF-I Ig and might also be able to associate with IGFBPs or (2) the polyclonal antibody might recognise more than one antigenic site on IGF-I. These data indicate that the anti-IGF-I Ig was protecting IGF-I from degradation, leading to a large plasma pool of IGF-I but that IGF-I could be transferred readily from the plasma pool to tissues. We suggest that administration of IGF-I in conjunction with a binding molecule similar to the antibody described here could provide the basis for effective IGF-I treatment strategy.

Ruakuric acid: a natural product from Aspergillus fumigatus

A new chroman derivative, named ruakuric acid, was isolated from a strain of Aspergillus fumigatus growing in conjunction with a coral lichen. The structure was determined as 6-acetyl-5-hydroxy-4-methoxy-chroman-2-carboxylic acid (mixture of 2,4-cis,trans isomers).

Photodynamic therapy (PDT) of the ciliary body with silicon naphthalocyanine (SINc) in rabbits

BACKGROUND AND OBJECTIVE

To investigate silicone naphthalocyanine (SINc; 0.5 mg/kg) for photodynamic therapy (PDT) of the ciliary body in pigmented rabbits.

STUDY DESIGN/MATERIALS AND METHODS

SINc was dissolved in canola oil by heating, emulsified with Tween-80, and given by ear vein. Pharmacokinetics were studied in frozen sections by fluorescence microscopy using a CCD camera-based, low light detection system with digital image processing at 1 hr and 24 hr (12 rabbits, 24 eyes total). A Ti:Sapphire laser delivered light at 770 nm by contact fiberoptic (1,000 microns; 80 mW/cm2;20,40 and 80 J/cm2). Controls (5 rabbits), received laser light at 770 nm without SINc. For comparison, eyes received continuous wave Nd:YAG laser by fiberoptic contact (0.8-1.2 J).

RESULTS

Localization studies showed intravascular distribution shifting to a ciliary body distribution at 24 hr. PDT at 1 hr and 24 hr postinjection showed a more selective destruction of the ciliary body at 24 hr. Ciliary processes treated at 24 hr showed infarction and marked edema with sparing of iris. Tissue thermal damage was minimal in PDT controls. Eyes treated with the Nd:YAG laser exhibited full-thickness thermal necrosis of iris, ciliary processes, and a fibrinous iridocyclitis. In contrast, eyes treated by PDT were quiet with thrombosis of superficial blood vessels.

CONCLUSION

Tissue photon penetration is good at 770 nm and thermal effects from the exciting laser alone were minimal. The ciliary processes of pigmented rabbits exhibit a selective retention of SINc and on that basis can be selectively destroyed with a minimum on thermal damage to nontarget tissues.

Photodynamic therapy of ocular melanoma with bis silicon 2,3-naphthalocyanine in a rabbit model

PURPOSE

To investigate bis (tri-n-hexylsiloxy) silicon 2,3-naphthalocyanine (SINc; 0.5 mg/kg) for photodynamic therapy of an experimental ocular melanoma in pigmented rabbits.

METHODS

SINc was dissolved in canola oil by heating, emulsified with Tween 80, and administered by ear vein. Pharmacokinetics were studied in frozen tumor sections by fluorescence microscopy using a charge coupled device, camera-based, low-light detection system with digital image processing at 1 and 24 hours. A Ti:sapphire laser and a microlens were used to deliver the light (770 nm; 40 mW/cm2; 20 J/cm2). A control rabbit received light without SINc.

RESULTS

Localization studies of SINc showed intravascular distribution shifting to a tumor stromal and perivascular distribution 24 hours after treatment. Tissue thermal damage after irradiation was minimal in the control. Exudative retinal detachments were not observed. Tumor destruction was observed, with sharp demarcation to a depth of 3.5 mm.

CONCLUSIONS

Tumor light penetration was good at 770 nm, and thermal effects from the exciting light alone were minimal. Photodynamic therapy with SINc resulted in localized tumor destruction reflecting the light beam path without damage to adjacent tissue or intraocular complications.

Stability of ondansetron hydrochloride injection in various beverages

The stability of ondansetron hydrochloride injection in beverages likely to be acceptable to patients was studied. Ondansetron hydrochloride injection (containing ondansetron 2 mg/mL) was added to apple juice, fruit punch, cherry-flavored drink, carbonated soft drinks, and hot tea to provide a nominal ondansetron concentration of 32.8, 64.5, or 95.2 micrograms/mL. Samples were stored at -3 to 28 degrees C (noncarbonated-beverage mixtures except tea), 2 to 28 degrees C (carbonated-beverage mixtures), and 25 degrees C (tea) and assayed for ondansetron concentration by high-performance liquid chromatography at 6, 24, 48, and 72 hours (noncarbonated-beverage mixtures except tea); 6, 24, and 48 hours (carbonated-beverage mixtures); and 1 hour (tea). More than 95% of the initial ondansetron concentration was retained in apple juice, fruit punch, cherry-flavored drink, Sprite, and Diet Coke throughout the periods studied. A precipitate formed immediately after ondansetron was added to hot tea, but the drug was chemically stable for at least one hour in this preparation. Ondansetron hydrochloride injection 32.7, 64.5, and 95.2 micrograms/mL (expressed as free base) was stable in various beverages when stored at -3 to 28 degrees C for up to 72 hours. Ondansetron at these same concentrations precipitated in hot tea preparations but was chemically stable for at least one hour.

Further characterisation of an IGF-I enhancing antibody: actions on IGF-I-induced hypoglycaemia and interaction with the analogue LR3IGF-I

We have previously shown that a polyclonal anti-IGF-I antiserum administered together with IGF-I potentiates IGF-I activity in vivo. The anti-IGF-I antiserum has a modest affinity for IGF-I, similar to that for enhancing IGFBPs, and treated animals have significantly higher circulating IGF-I concentrations than their controls. Our recent findings have demonstrated that the anti-IGF-I activity decreases the clearance of IGF-I by at least 2-fold and that it abolishes the acute hypoglycaemic action of a single subcutaneous dose of IGF-I. Interestingly, we have been unable to demonstrate potentiation of the growth-promoting activity of the potent non-IGFBP binding IGF-I analogue LR3IGF-I, even though the analogue binds to the antiserum in vitro; rather native IGF-I/antibody complexes perform even better than LR3IGF-I. In IGF-I/antibody-treated dwarf rats, most IGF-I may be found in an uncharacterised high molecular weight antibody complex which is probably responsible for improved IGF-I performance. Thus, the anti-IGF-I antibody may be behaving in a similar manner to a high molecular weight IGFBP and is effective in potentiating IGF-I action in vivo.

Photodynamic laser cyclodestruction with chloroaluminum sulfonated phthalocyanine (CASPc) or Photofrin (PII) vs. Nd:YAG laser cyclodestruction in a pigmented rabbit model

BACKGROUND AND OBJECTIVE

To investigate Photofrin (PII) and CASPc for photodynamic therapy (PDT) of the ciliary body in rabbits.

STUDY DESIGN/MATERIALS AND METHODS

PII (10 mg/kg) or CASPc (1 mg/kg) was given by ear vein. Pharmacokinetics were studied in frozen sections by fluorescence microscopy (CCD camera based low light detection system with digital image processing) at 1 and 24 h (8 rabbits; 16 eyes). Laser light was delivered (argon pumped dye laser; 630 and 675 nm; 8 rabbits; 16 eyes) by contact fiberoptic. To compensate for iris attenuation, irradiance was 125 mW/cm2 (20, 40, 80, or 160 J/cm2). Controls (4 rabbits; 8 eyes) received laser light without photochemicals (OD) and for comparison, continuous wave Nd:YAG laser by fiberoptic (0.8-1.2J; OS).

RESULTS

Localization studies showed intravascular distribution with some selective ciliary body distribution at 24 h (PII > CASPc). Rabbits treated with PII or CASPc exhibited variable amounts of gross ciliary body edema, infarction, and necrosis by 24-48 h. This response was not seen in PDT control tissues; damage was seen in the iris and ciliary body, with partial vacuolization of the pigment epithelium.

CONCLUSION

PDT may offer a more selective approach to ciliary body destruction. A small but significant thermal effect was seen during PDT from melanin photon uptake with damage to iris and ciliary body. Thermal damage and potential interaction with ocular visual pigments may limit use of these photochemicals and wavelengths for PDT of the ciliary body.

Wound cleansing by irrigation for implant surgery

Wound irrigation is an adjunct to all implant surgeries involving surgical incisions or arthroplasties. An understanding of the physics of wound irrigation provides a scientific basis for recommending wound irrigation systems for implant surgery. When inserting implants through surgical incisions, a low-pressure irrigation system is recommended for removing blood from the wound surface. In contrast, high-pressure irrigation systems are indicated to cleanse the intramedullary canal before cemented arthroplasty. With the advent of static and dynamic pressure transducers, irrigation systems can now be specifically designed to achieve these goals.

Electrophysiologic monitoring in the intensive care unit

Electroencephalography (EEG) and evoked potential studies are established monitoring tools in the neurological intensive care unit (ICU). These neurophysiologic techniques provide information on physiological state and response to therapy, and may aid diagnosis and prognosis. Serial studies or continuous monitoring may enable changes to be detected prior to irreversible deterioration in the patient's condition. Current computer technology allows simultaneous display and correlation of electrophysiologic parameters, cardiovascular state and intracranial pressure (ICP). Continuous EEG monitoring in the ICU has been shown to have a decisive or contributing impact on medical decision making in more than three-quarters of patients. In addition, continuous EEG monitoring has revealed previously unsuspected non-convulsive seizures in one-third of patients. SEPs and BAEPs can provide useful prognostic information in coma-however, these tests are etiologically nonspecific and must be carefully integrated into the clinical situation. Motor evoked potentials offer a potentially useful tool for evaluating motor system abnormalities in the ICU.

Metabolism of styrene by Rhodococcus rhodochrous NCIMB 13259

Rhodococcus rhodochrous NCIMB 13259 grows on styrene, toluene, ethylbenzene, and benzene as sole carbon sources. Simultaneous induction tests with cells grown on styrene or toluene showed high rates of oxygen consumption with toluene cis-glycol and 3-methylcatechol, suggesting the involvement of a cis-glycol pathway. 3-Vinylcatechol accumulated when intact cells were incubated with styrene in the presence of 3-fluorocatechol to inhibit catechol dioxygenase activity. Experiments with 18O2 showed that 3-vinylcatechol was produced following a dioxygenase ring attack. Extracts contained a NAD-dependent cis-glycol dehydrogenase, which converted styrene cis-glycol to 3-vinylcatechol. Both catechol 1,2- and 2,3-dioxygenase activities were present, and these were separated from each other and from the activities of cis-glycol dehydrogenase and 2-hydroxymuconic acid semialdehyde hydrolase by ion-exchange chromatography of extracts. 2-Vinylmuconate accumulated in the growth medium when cells were grown on styrene, apparently as a dead-end product, and extracts contained no detectable muconate cycloisomerase activity. 3-Vinylcatechol was cleaved by catechol 2,3-dioxygenase to give a yellow compound, tentatively identified as 2-hydroxy-6-oxoocta-2,4,7-trienoic acid, and the action of 2-hydroxymuconic acid semialdehyde hydrolase on this produced acrylic acid. A compound with the spectral characteristics of 2-hydroxypenta-2,4-dienoate was produced by the action of 2-hydroxymuconic acid semialdehyde hydrolase on the 2,3-cleavage product of 3-methylcatechol. Extracts were able to transform 2-hydroxypenta-2,4-dienoate and 4-hydroxy-2-oxopentanoate into acetaldehyde and pyruvate.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation and management of the painful hip in childhood

The cause of the painful hip in childhood must be identified quickly to avoid permanent damage resulting from conditions such as septic arthritis. A painful hip may be the presenting feature of a number of conditions and their investigation and management are described here.

Protein profiles of Brucella suis and Brucella abortus in isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis

The protein profiles of five field isolates of Brucella suis and four field isolates of B. abortus were examined. Isoelectric focusing of soluble proteins from cell sonicates produced 28 bands common to both species, with a further 10 bands being unique to a species. No intraspecies variation was detected. Sodium dodecyl sulfate extracted proteins were resolved by polyacrylamide gel electrophoresis. The proteins were transferred to nitrocellulose and then stained. These techniques allowed the demonstration of 35 bands which were common to both species, with a further 15 bands which were unique to one of the two species. Again, no intraspecies variation was detected.

Injuries to the physis by extravasation. A rare cause of growth plate arrest

We report two cases of deformity of the ankle caused by physeal damage secondary to extravasation of an intravenous infusion in infancy. The possible mechanisms of injury to the physis are discussed.

Injuries to the physis by extravasation. A rare cause of growth plate arrest

We report two cases of deformity of the ankle caused by physeal damage secondary to extravasation of an intravenous infusion in infancy. The possible mechanisms of injury to the physis are discussed.

Epilepsy and mental decline

Experience with prolonged seizures in animal models and humans teaches that cellular injury and cognitive impairment can occur in epilepsy. Status epilepticus probably causes cerebral injury and cognitive dysfunction if it is of long duration; however, studies of electroconvulsive therapy do not support the idea that repeated seizures alone produce a decline in cognitive function. Although many factors related to seizures may correlate with cognitive impairment in certain groups of patients with epilepsy, prospective studies do not support the premise that cognitive impairment develops or progresses in a population of epilepsy patients. When impairment is present, its origin appears to be multifactorial. In addition to the seizures and associated seizure variables (including anticonvulsant medications), interictal epileptiform discharges and the perceptions of the patients and others also may play major roles.