Bioactive carotanes from Trichoderma virens

Four new metabolites with carotane skeletons, trichocaranes A (1), B (2), C (3), and D (4), were isolated from Trichoderma virens and their structures established by the interpretation of NMR and mass spectroscopic data. The trichocaranes significantly inhibited the growth of etiolated wheat coleoptiles: 40% at 10(-4) M with 1 and 2 and 86% at 10(-3) M with 3.

Pathophysiology of and prophylaxis against late ahmed glaucoma valve occlusion

PURPOSE

To understand the pathophysiology of late Ahmed Glaucoma Valve failures and devise strategies to minimize this problem.

METHODS

One hundred sixty eyes that had undergone Ahmed Glaucoma Valve implants by one surgeon were retrospectively reviewed. Six eyes with late (greater than 3 months) Ahmed Glaucoma Valve occlusion requiring operative intervention were identified. Two of these eyes underwent initial successful transcameral drainage tube irrigation and four initially required Ahmed Glaucoma Valve exchange. Intraoperative images, postoperative histologic analysis, and Ahmed Glaucoma Valve handling experiments were performed.

RESULTS

Two eyes with late occlusion (33%; 1.25% of total implants) were initially successfully treated with irrigation alone. A gap between the valve cover and valve body junction allowed fibrovascular ingrowth and produced valve failure ultimately in five of six eyes (83%; 3.1% of total implants). This gap could be produced by grasping the device along the center line, indenting the valve cover, and damaging the plastic rivets attaching the valve cover to the valve body. Handling the Ahmed Glaucoma Valve outside this "no touch zone" eliminated this problem.

CONCLUSIONS

Leaflet adhesion has a low incidence and may be treated by transcameral drainage tube irrigation. Late onset distal occlusion is best treated by Ahmed Glaucoma Valve exchange with respect for the "no touch zone." Respecting the "no touch zone over the valve mechanism should avoid creation of gaps between the valve cover and valve body junction, which allow secondary fibrovascular ingrowth.

Female baboons do not raise the stakes but they give as good as they get

We used data from four chacma baboon, Papio cynocephalus ursinus, troops, living in two populations, to test the raise the stakes (RTS) strategy of reciprocity. Female baboons did not raise the stakes either within or across grooming bouts. Instead they time-matched grooming contributions and divided grooming into short episodes. In addition, analysis of the grooming behaviour of frequently versus infrequently grooming dyads did not reveal differences in grooming patterns predicted by the RTS strategy. We suggest time constraints preclude the escalation of grooming bout length as required by RTS; the data were more consistent with a strategy of give as good as you get. However, this strategy could not explain all the patterns observed, and we conclude that biological market theory represents a more appropriate framework for investigating female grooming dynamics than dyadic games based on the iterated prisoner's dilemma. We suggest that competitive altruism among individuals acts as a market force influencing an individual's value as a grooming partner. Copyright 2000 The Association for the Study of Animal Behaviour.

Enhancement of insulin-like growth factor I activity by novel antisera: potential structure/function interactions

Insulin-like growth factor I (IGF-I) is essential for normal growth and development, regulating cell proliferation, differentiation, and survival. Little IGF-I exists in the free form; rather, it is bound to one of a family of six specific IGF-binding proteins (IGFBPs). Usually, IGFBPs have a high affinity for IGF-I and inhibit its activity. Intriguingly, some IGFBPs also potentiate IGF-I action; the precise mechanism of this is unclear, but it is thought to include modification of the IGFBP to lower its affinity for IGF-I. We have previously generated a novel antihuman (h) IGF-I antiserum that, instead of inhibiting IGF-I activity, enhances it in vivo. As the enhancing anti-IGF-I antiserum and potentiating IGFBPs share several properties with regard to IGF action, the antibody may provide a model for examining the actions of enhancing IGFBPs. In this study we demonstrate that the antiserum can also enhance IGF-I activity in vitro, assessed as cell number of a bovine fibroblast cell line, suggesting that its actions might not merely be confined to changing the kinetics of IGF-I clearance or degradation. Epitope scanning using overlapping octamer and hexamer peptides spanning the entire sequence of IGF-I indicates that the enhancing antiserum recognizes a specific linear region spanning the C-terminal region of the C domain and the proximal A domain (residues Ser33 to Cys47), and that this recognition is not present in nonenhancing antisera. Further, this region is located on the opposite surface of IGF-I from putative type 1 receptor-binding residues, allowing the possibility that the antiserum might be able to modulate IGF-I receptor binding. Antibodies raised against a synthetic peptide corresponding to Ser33 to Cys47 of IGF-I also potentiated IGF-I activity in vivo. As IGF-I may be beneficial in various clinical conditions associated with catabolism or cell repair, we suggest that this potentiating anti-IGF-I antiserum has favorable properties that could form a basis for therapeutic strategy.

Orthopaedic manifestations of mucolipidosis III: an illustrative case

The musculoskeletal manifestations of mucolipidosis III include short stature, claw hands, carpal tunnel syndrome, and limited joint mobility. This article presents a series of complex orthopaedic problems, including avascular necrosis of the talus, encountered in one such patient whose presentation had initially given the impression of a mild form of the disease.

Photosensitive epilepsy studied by functional magnetic resonance imaging and magnetic resonance spectroscopy

PURPOSE

To study metabolic and hemodynamic correlates of photic stimulation-triggered discharges.

METHODS

Simultaneous EEG, functional MRI (tMRI) and magnetic resonance spectroscopy (MRS) were performed in nine patients with photosensitive epilepsy and in 12 normal subjects.

RESULTS

Prominent visual cortex activation was seen in all normal subjects and patients, and no tMRI-registered hemodynamic abnormalities were correlated with the brief photoparoxysmal spike-wave activity evoked in the photosensitive patients. However, irrespective of the presence of a spike-wave response to the photic stimulation, the photosensitive patients showed four findings not seen in the normal subjects: (a) slightly, but significantly, elevated lactate levels in the occipital cortex in the resting state; (b) an increased area of visual cortical activation with photic stimulation; (c) simultaneous with the occipital cortex stimulus-induced increased fMRI signal, there were noncontiguous areas of signal attenuation most prominent in perirolandic regions; and (d) a marked decrement (undershoot) of fMRI signal intensity immediately after the photic stimulation in the occipital cortex and in the region of the posterior cingulate gyrus.

CONCLUSIONS

These findings suggest abnormal interictal metabolism and increased vascular reactivity in the photosensitive patients.

Hemodynamic and metabolic aspects of photosensitive epilepsy revealed by functional magnetic resonance imaging and magnetic resonance spectroscopy

PURPOSE

To study in humans the hemodynamic and metabolic consequences of both photic stimulation-triggered and spontaneous generalized epileptiform discharges.

METHODS

Simultaneous EEG, functional magnetic resonance imaging (fMRI) and MR spectroscopy were performed in a 1.5-T scanner in 16 patients with generalized epilepsy, including nine with photosensitive epilepsy, and 12 normal subjects.

RESULTS

With a flash stimulation duration of 2 s, prominent visual cortex activation was seen in all normals and patients. There were no fMRI-registered hemodynamic abnormalities found in relation to the brief photoparoxysmal spike-wave activity evoked in the photosensitive patients. However, irrespective of the presence of a spike-wave response to the photic stimulation, the photosensitive patients showed four unique findings compared with normals: (a) slightly, but significantly, increased lactate levels in the occipital cortex in the resting state, (b) an increased area of visual cortical activation with photic stimulation, (c) simultaneous with the occipital cortex stimulus-induced increased fMRI signal there were noncontiguous areas of signal attenuation most prominent in perirolandic regions, and (d) a marked decrement (undershoot) of fMRI signal intensity immediately after the photic stimulation in the occipital cortex and in the region of the posterior cingulate gyrus.

CONCLUSIONS

These findings suggest abnormal interictal metabolism and increased vascular reactivity in the photosensitive patients.

Leg lengthening in spinal dysraphism

Spinal dysraphism may lead to limb inequality and foot deformities. Fears have been expressed regarding limb lengthening in such patients because of potential sequelae in relation to their peripheral neurologic abnormalities. We performed Ilizarov lengthening of the lower limb on seven community walkers with spinal dysraphism. The procedure was well tolerated with no increase in sepsis, soft-tissue, or bony complications compared with patients undergoing lengthening for reduction anomalies. All the patients mobilised rapidly after frame application and returned to their previous functional level within 3 months of plaster removal.

Action of long(R3)-insulin-like growth factor-1 on protein metabolism in beef heifers

Insulin-like growth factor-1 (IGF-1) is perhaps the most important endogenous factor controlling growth. Most studies to date in livestock have shown that IGF-1 has greatest efficacy when animals are in a catabolic state. We have determined the effects of an i.v. infusion of the IGF-1 analog Long(R3)-IGF-1 on protein metabolism in beef heifers that were slowly losing liveweight because of restricted feeding. There was a tendency for both whole-body protein and skeletal muscle protein to be conserved in Long(R3)-IGF-1-treated heifers. Long(R3)-IGF-1 administration markedly reduced the plasma concentrations of all amino acids measured and glucose. There was a significant change in the profile differences of endogenous plasma IGF-1 concentrations during the 8-hr infusion period, with plasma IGF-1 decreasing sharply in the test group. There was a significant difference in mean profiles for plasma IGF-2 between the test and control groups. Overall, plasma IGF-2 for the control group decreased only slightly over time (about 40 ng/ml), whereas the test group decreased dramatically (by about 140 ng/ml). Increased plasma concentrations of a 31-32-kDa IGF-binding protein (possibly IGF-binding protein-1) in the treated group was detected by radioligand blot. We found that Long(R3)-IGF-1 infusion tended to preserve whole-body and muscle protein in beef heifers on a low-quality diet, and suggest that further investigation of this treatment may provide an alternative approach to reducing weight loss during the dry season.

Intermediate-term clinical experience with the Ahmed Glaucoma Valve implant

PURPOSE

We studied the intermediate-term clinical experience with the Ahmed Glaucoma Valve implant (New World Medical, Inc, Rancho Cucamonga, California).

METHODS

In this multicenter, retrospective case series, we studied 159 eyes (144 patients) treated with the Ahmed Glaucoma Valve with a mean +/- SEM (standard error of mean) follow-up of 13.4 +/- 0.7 months (range, 4 to 44 months). The mean +/- SEM age was 60.9 +/- 1.9 years (range, 0.1 to 103 years). Surgical success was defined as intraocular pressure less than 22 mm Hg and greater than 5 mm Hg without additional glaucoma surgery and without loss of light perception. Postoperative use of antiglaucoma medications was not a criterion for success or failure. The definition of hypotony was intraocular pressure of 5 mm Hg or less in two consecutive visits.

RESULTS

Intraocular pressure was reduced from a mean of 32.7 +/- 0.8 mm Hg before surgery to 15.9 +/- 0.6 mm Hg (P < .0001) at the most recent follow-up after surgery. The number of antiglaucoma medications was decreased from 2.7 +/- 0.1 before surgery to 1.1 +/- 0.1 after surgery (P < .0001). The cumulative probability of success was 87% at 1 year and 75% at 2 years after surgery (Kaplan-Meier life-table analysis). Postoperatively, 24 (15%) of 159 eyes had intraocular pressure greater than or equal to 22 mm Hg. The visual acuity was improved or within one Snellen line in 131 eyes (82%). Complications occurred in 75 eyes (47%), the majority of which did not affect surgical outcome. The most common complication was obstruction of the tube, which was observed in 17 eyes (11%). Transient postoperative hypotony was found in 13 eyes (8%).

CONCLUSIONS

The Ahmed Glaucoma Valve implant is effective in lowering intraocular pressure, and postoperative hypotony is not commonly associated with this implant.

Koninginin G, a new metabolite from trichoderma aureoviride

A new metabolite, koninginin G (1), was isolated from a strain of Trichoderma aureoviride and its structure established by the interpretation of spectroscopic data. The metabolite significantly inhibited the growth of etiolated wheat coleoptiles by 56% at 10(-3) M.

Case report. Post-traumatic tibial recurvatum: resolution with growth

The outcome of proximal tibial fractures in children is often complicated by the development of malalignment. Progressive valgus deformity is frequently seen, but is known to correct spontaneously in a high proportion of cases; however, recurvatum of the tibia usually requires surgical intervention. We present a child with a proximal tibial metaphyseal fracture who developed increasing tibial recurvatum which corrected spontaneously.

Leptin: its pharmacokinetics and tissue distribution

OBJECTIVE

The pharmacokinetics and tissue distribution of leptin in rats was investigated.

DESIGN

A catheter was inserted in the right jugular vein of rats on the day prior to experiment. The next day, blood was sampled and then a tracer dose of radioiodinated hormone was administered via the catheter. Thereafter, small (200 microl) samples of blood were taken at regular intervals. Two experiments were conducted over different sampling times. TCA precipitated radioactivity was counted in samples of plasma and tissues. Pharmacokinetic parameters were calculated after fitting a bi-exponential equation describing a two-pool model of plasma leptin distribution. Selected time-point plasma samples were fractioned using size exclusion chromatography and the leptin distribution determined.

RESULTS

The two pool model described the pharmacokinetics of leptin in two forms: an initial fast decaying pool (t(1/2) = 3.4 min) and a slower decaying pool (t(1/2) = 71 min) with an overall clearance rate of 6.16 ml/min/kg. Size exclusion chromatography showed a persistent peak (all time-points tested) of 125I-leptin corresponding to the plasma albumin peak. The size of the free 125I-leptin peak became diminished or absent in later time-point plasma samples. Tissue distribution of leptin at 60 min and 180 min time-points showed that the small intestine contained the highest concentration of leptin, almost four times the level found in kidneys, liver, stomach and lungs. 125I-leptin was least abundant in skin, muscle, heart, caecum and brain.

CONCLUSION

The pharmacokinetics of leptin are affected by three important factors: 1) its ability to bind to a plasma carrier molecule which increases its half-life; 2) its association with abundant peripheral tissue binding sites which creates an additional pool of leptin and 3) the rate of synthesis of leptin which may be less important than originally believed as the prolonged half-life and the additional pool of tissue binding sites are important factors in determining its plasma concentration.

Late diagnosis and treatment of crush injuries of the fingertip in children

Crush injuries of the fingertip are common in childhood. In the course of six months seven cases presented to our department, five of which were S III type injuries [Van Beek et al., Hand Clinics 1990; 6(1): 23-35], that is a sterile matrix laceration with a tuft fracture. In all but one case the severity of the injury was not appreciated at initial presentation leading to an average delay in definitive treatment of 6.6 days. Junior doctors need to be aware of the potential severity of these injuries and the difficulty in their diagnosis. Radiographs should routinely be taken and the presence of a fracture should strongly suggest the presence of a nailbed injury. Despite delays in diagnosis definitive treatment can result in good cosmetic and functional results even after a delay of up to two weeks.

Functional activity of antibodies at the bovine beta2-adrenoceptor

Antibodies that can activate beta2-adrenoceptors (beta2-AR) have the potential to mimic the anabolic effects of beta-agonist drugs, such as clenbuterol. In this study, antibodies were raised in rabbits against two peptide analogues of the human beta2-adrenoceptor (beta2-AR): One peptide corresponded to the complete second outer loop of the receptor (24 amino acids; H24T), and the second peptide was a truncated version of the first (13 amino acids; H13C). Following affinity purification, the antibodies were screened to detect interaction with beta2-AR in vitro. Membrane proteins from transformed Escherichia coli that express the beta2-AR were separated using SDS PAGE and transferred to nitrocellulose sheets. Immunoblotting revealed a single protein band (39,000 Da) that was recognized by the affinity-purified anti-H24T antibodies. However, the anti-H13C antibodies did not recognize any protein bands in immunoblots. In ligand binding studies, anti-H24T antibodies at a concentration of 50 nM, increased the affinity (KD) of the radiolabeled antagonist [125I]iodocyanopindolol for the bovine beta2-AR from 31.7 pM to 25.3 pM (P < .05) without changing the receptor number. Anti-H13C antibodies had no effect on ligand binding. In competitive ligand binding experiments, there was no effect of antibodies on the affinity of bovine beta2-AR for the agonist (-)-isoproterenol. However, functional activity of anti-H24T antibodies was demonstrated in an organ bath study. The presence of antibodies caused a leftward shift in the concentration-response curve for (-)-isoproterenol-induced relaxation of isolated bovine smooth muscle strips. Values for pD2 (-log EC50) were reduced in the presence of 10 nM antibody (8.62 +/- .11) compared to controls (8.30 +/- .08; P < .05). Anti-H13C antibodies had no effect on (-)-isoproterenol-induced smooth muscle relaxation. These studies have demonstrated recognition, interaction, and functional activity of site-directed antibodies at the beta2-AR. Further studies will determine whether antibodies that potentiate activity at the beta2-AR may be evoked by the active immunization of cattle with the peptide H24T, and if so, whether this will cause the repartitioning of nutrients in a manner analogous to conventional beta2-agonists and thus provide an alternative to the use of xenobiotic compounds.

Triggering in the mucopolysaccharidoses

Upper limb dysfunction, particularly in relation to skeletal dysplasia and median nerve dysfunction, is well recognized in the mucopolysaccharidoses and mucolipidoses. This is of increasing importance because bone marrow transplantation has dramatically improved survival without changing the musculoskeletal manifestations. Triggering at the A1 pulley and more distally has been described in these patients. We report two such cases and four other patients who were noted to have triggering at the carpal tunnel in association with carpal tunnel syndrome. Five of the six patients consented to surgical intervention with favorable outcomes.

1,4-dihydro-2,3-quinoxalinediones as potential flavin metabolites and excitatory amino acid receptor ligands. Part 1: Synthesis and pharmacological evaluation of the benzylic oxidation series of 1,4-dihydro-6,7-dimethyl-2,3-quinoxalinedione

A series of five 6,7-disubstituted 1,4-dihydro-2,3-quinoxalinediones was prepared, two of which are known microbial flavin metabolites and three of which are potential flavin metabolites. Four of the five compounds inhibited specific binding of [3H]-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid ([3H]AMPA), [3H]kainic acid, and [3H]6-cyano-1,4-dihydro-7-nitro-2,3-quinoxalinedione ([3H]CNQX) in rat brain homogenate fractions, with IC50 values in the low micromolar range (the fifth compound competed only with [3H]CNQX). Two of the compounds were moderately potent AMPA antagonists in an in vitro functional test.

Regulation of insulin-like growth factor I (IGF-I) bioactivity in vivo: further characterization of an IGF-I-enhancing antibody

We have previously demonstrated the ability of a polyclonal antibody raised against human insulin-like growth factor I (IGF-I) to potentiate, rather than inhibit, the growth-promoting activity of IGF-I. The anti-IGF-I Ig had a modest affinity for IGF-I, protected IGF-I from degradation, and reduced the IGF-I clearance rate while allowing efficient transfer of peptide from the circulation, leading to the suggestion that the antiserum might be behaving in an analogous manner to enhancing IGF-binding proteins (IGFBPs). The purpose of these studies was to investigate further the characteristics of this antiserum as a means of assessing the importance of IGF-I associated with circulating high mol wt IGFBPs to serve as a bioavailable reservoir of IGF-I peptide. 1) Epitope scanning using sequential and overlapping peptides spanning the entire length of IGF-I revealed one major linear region of anti-IGF-I Ig binding to IGF-I comprising the C-terminal region of the C-domain and the N-terminal region of the A-domain (Arg36-Ile43), a region not associated with receptor or IGFBP binding. 2) The fact that the antibody could potentiate IGF-I whether administered as a preincubated complex or separately indicated that complex formation could occur in the presence of IGFBPs in vivo. 3) The ability of the antibody to attenuate the acute hypoglycemic actions of IGF-I and LR3IGF-I was assessed by pretreating dwarf rats with either anti-IGF-I Ig or nonimmune Ig; 1 h after s.c. administration of peptide, plasma glucose levels decreased by about 4 mM (P < 0.001) in rats pretreated with nonimmune Ig. The duration of hypoglycemia was more prolonged in the LR3IGF-I-treated rats (P < 0.01). Neither IGF-I or LR3IGF-I induced any decrease in circulating glucose concentrations in the rats pretreated with the anti-IGF-I Ig, suggesting that the antibody gave protection against inappropriate acute IGF-induced hypoglycemia. 4) The potentiating effects of the anti-IGF-I Ig on the anabolic actions of IGF-I and LR3IGF-I were compared in dwarf mice. The anti-IGF-I Ig potentiated the increase in whole body weight gain induced by IGF-I by over 3-fold (P < 0.001), but did not change the anabolic action of LR3IGF-I despite its ability to double circulating levels of both IGF peptides. It is, therefore, possible that part of the mechanism of action of the anti-IGF-I Ig involves transfer of IGF-I to smaller mol wt binding proteins. These data confirm the potential of IGFBP-associated IGF-I to act as a reservoir of peptide and to regulate IGF-I activity in vivo.

Evaluation and prognostication in coma

Electroencephalography (EEG) and evoked potential (EP) studies are neurophysiologic techniques which 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 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 two-thirds of patients. Somatosensory and auditory EPs can provide useful prognostic information in coma patients, however, these tests are etiologically non-specific and must be carefully integrated into the clinical situation. Motor EPs offer a potentially useful tool for evaluating motor system abnormalities in the ICU. Thus, neurophysiologic tests are established monitoring tools in the neurological intensive care unit.