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Nature-based solutions to climate change are growing policy priorities yet remain hard to quantify. Here we use remote sensing to quantify direct and indirect benefits from community-led agroforestry by The International Small group and Tree planting program (TIST) in Kenya. Since 2005, TIST-Kenya has incentivised smallholder farmers to plant trees for agricultural benefit and to sequester CO2. We use Landsat-7 satellite imagery to examine the effect on the historically deforested landscape around Mount Kenya. We identify positive greening trends in TIST groves during 2000–2019 relative to the wider landscape. These groves cover 27,198 ha, and a further 27,750 ha of neighbouring agricultural land is also positively influenced by TIST. This positive ‘spill-over’ impact of TIST activity occurs at up to 360 m distance. TIST also benefits local forests, e.g. through reducing fuelwood and fodder extraction. Our results show that community-led initiatives can lead to successful landscape-scale regreening on decadal timescales.

Purpose To present the visual and safety outcomes of surgery for primary idiopathic macular holes including predictors of visual acuity and the impact of combined phacovitrectomy surgery. Design Registry-style, prospective, nonrandomized, observational cohort study. Participants Patients with idiopathic macular holes undergoing primary surgery. Methods Surgeons were invited to submit clinical details of all macular hole cases receiving surgery. Baseline demographic and clinical information, and details of surgical intervention were collected. Primary follow-up data were collected at 3 months postoperatively or before revision surgery, and surgeons were also asked to submit data at 12 and 24 months postoperatively. Main Outcome Measures Visual acuity improvement ≥15 letters and ≥0 letters, change in mean visual acuity, visual acuity ≥70 letters (20/40), retinal detachment, and endophthalmitis. Results A total of 2455 eyes of 2366 patients were included in the study, and hole closure was achieved in 95.6% of eyes with a single procedure. Mean baseline vision was 48.3 letters. The proportion of successful eyes improving ≥15 letters at 3, 12, and 24 months was 59.1%, 69.4%, and 68.2%, respectively. The mean improvement in acuity at 3, 12, and 24 months was 16.0, 19.2, and 23.6 letters, and 92.4%, 93.4%, and 95.8% improved ≥0 letters at 3, 12, and 24 months, respectively. Eyes receiving SF6 gas had better visual acuities at all time points postoperatively (adjusted effect 3.4, 3.1, and 4.6 letters better at 3, 12, and 24 months vs. longer-acting gas, respectively). Combined phacovitrectomy in phakic eyes was associated with better corrected visual acuity postoperatively (vs. vitrectomy surgery alone), a difference that vanished when eyes went on to have subsequent cataract surgery. The rate of retinal detachment postoperatively was 1.3%, and the odds of detachment were greater in eyes receiving longer-acting gases versus SF6 gas (adjusted odds ratio, 2.2; 95% confidence interval, 1.04–4.77; P = 0.039). There were no reported cases of endophthalmitis. Conclusions Macular hole surgery substantially improved acuity in approximately two thirds of patients and was seldom associated with loss of vision. SF6 gas was associated with better visual outcomes, an effect that warrants further study.

Purpose To describe the anatomic and visual outcomes of eyes undergoing reoperation after failed primary surgery for idiopathic macular hole. Design Prospective registry study. Participants One hundred three patients who had undergone failed macular hole surgery. Methods Unclosed idiopathic macular holes were identified from a large national prospective registry run by the Australian and New Zealand Society of Retinal Specialists. Unclosed idiopathic macular holes were defined as idiopathic macular holes that underwent vitrectomy surgery for the first time, but were never observed to close in the postoperative period. Surgeons were contacted to submit retrospectively details of subsequent management and long-term outcome of these eyes. Main Outcome Measures Macular hole closure; visual acuity (VA) change relative to baseline at 3, 12, and 24 months; and hole size at all time points. Results One hundred three patients with failed macular hole surgery were identified, among whom 53 underwent reoperation, 49 did not, and 1 was lost to follow-up. Macular hole closure was achieved in 45 of 53 patients (85%) undergoing revision surgery. Mean change in VA from baseline in eyes undergoing revision surgery versus eyes that did not was +2.8 letters versus −1.9 letters at 3 months ( P = 0.278), +8.2 letters versus −1.9 letters at 12 months ( P = 0.167), and +18.3 letters versus −3.4 letters at 24 months ( P = 0.022). Thirty-six percent of eyes with reoperated holes showed improved VA of 15 letters or more at 3 months after operation, increasing to 48% at 12 months and 65% at 2 years. Before revision surgery, mean macular hole size was observed to increase from 483 μm to 562 μm after failed primary surgery ( P = 0.046). Conclusions In eyes undergoing revision surgery, reoperation for unclosed macular holes was significantly better than observation, although these visual gains took some time to occur. The surgical success rate was lower than that for primary idiopathic macular hole. The selection criteria for revision surgery need to be defined.

The further optimisation of the novel lead compound CGH752 (Fig. 1) is described. By introducing various substituents into the 6-position of the 3,3-dimethyltetrahydroquinoline (DMTHQS) ring we have been able to favourably affect the in vitro and in vivo activity, and the pharmacokinetics of such compounds. One of the inhibitors synthesised (CGH1484) is bioavailable and shows efficacy in animal models of thrombosis.

Mitsubishi's MD-805, a potent and selective inhibitor of thrombin which contains four stereogenic centers, has been the starting point for an optimization program. A systematic synthetic study resulted in thrombin inhibitors achiral at P2 and P3 but with a 10-fold increase in potency over the original lead. A number of 4-substituted piperidines were synthesized and examined as replacements for 2-carboxy-4-methylpiperidine at P2; 4-fluoroethylpiperidine (FEP) among others provided inhibitors (e.g. 45g) of increased potency. An enantioselective route was developed to 3(R)-methyl-1,2,3,4-tetrahydroquinolinesulfonyl chloride. Inhibitors containing this enantiomerically pure P3 (42d) had similar potency to the racemic material and provided support, with modeling studies, for the preparation of the gem 3,3-disubstituted compounds. A series of inhibitors containing the novel 3, 3-dimethyl-1,2,3,4-tetrahydroquinolinesulfonyl (DMTHQS) P3 (Table 5) were synthesized and showed a similar activity profile as the monomethyl series. The combination of P3-DMTHQS, P2-FEP, and P1-arginine (45g) had a K(i) of 6 nM (MD-805 K(i) = 85 nM). In animal models of both venous and arterial thrombosis, one inhibitor (42e) was shown to produce a dose-dependent inhibition of thrombus formation that in some situations was superior to that of MD-805.

The application of selection criteria, based on potency and physicochemical parameters, to a candidate library of thrombin inhibitors is described. The utility of the approach is exemplified by the discovery of a potent, selective and bioavailable thrombin inhibitor 62.

Backbone, sugar and pendant-group modifications were shown to influence the anticoagulant properties of a 20-mer oligonucleotide in human plasma in vitro. The pharmacokinetics, tissue-distribution and metabolism of a chimeric oligonucleotide (CGP 69845A), which had reduced anticoagulation properties, were compared with the analogous phosphorothioate oligodeoxynucleotide (CGP 69846A) in a tumour-bearing mouse model.

Despite the development of many large systems, small-scale irrigation still covers vast areas of Asia and often constitutes one-third to two-thirds of the entire irrigation sector. However, many Asian countries have rather poor records of small-scale systems both because of their number and dispersion, and because of their quite varied and sometimes rather disguised forms. Although the endurance of small systems over time is remarkable, they are under constant stress. The nature of the social and technical challenges that face small-scale irrigation systems today is examined through case studies of two very different types of small systems: hill irrigation and tank systems. The paper makes suggestions about new roles for the government vis-a-vis small irrigation systems.

A series of di- and tri-substituted 6-phenyl-4,5-dihydro-2H-pyridazine-3-ones is described. The compounds were designed to be antithrombotics and were assessed for their inhibitory properties on platelet aggregation and on thrombus formation in an arteriovenous shunt in the rat. The synthesis and physical properties of the compounds are described. The structure-activity relationships reveal that non-aromatic nitrogen-containing heterocycles can confer high activity on the 6-phenyl-pyridazinone system, provided they are combined with an additional electron-withdrawing substituent in the phenyl ring. The most potent compounds ( 8i, 8b ) had an ED min of 1–3 mg/kg after oral administration in the thrombus formation test.

The role of thrombin in the formation of arterial thrombi is poorly understood. With the new availability of the specific thrombin inhibitor, recombinant desulphatohirudin, in large quantities this is now under investigation. A new model of arterial thrombosis in rats is described where a thrombus is formed on a mechanically injured vessel in vivo. Both platelet and fibrin deposition is inhibited by a recombinant hirudin (CGP 39393) at doses which prolong the activated partial thromboplastin time (APTT) to no more than 3–4 times the control level.In contrast, both unfractionated heparin and Fragmin only inhibit thrombosis when the APTT is excessively prolonged (i.e. to greater than 15 times the control value). It is concluded that CGP 39393 is an effective antithrombotic in arterial thrombosis at lower levels of anticoagulation than either heparin or Fragmin.

A series of monocyclic and bicyclic amino acids have been synthesised and incorporated into thrombin inhibitors based on CGH728, an analogue of the Mitsubishi compound MD805. Benzthiazolylalanine (Bta) was found to be a good non-polar substitute for arginine at the P1 position, yielding compounds with low nanomolar potency and good selectivity for thrombin.

The optimisation of the P2 pharmacophore in a series of thrombin inhibitors is described. The interaction of a number of piperidine P2 functionalities with lysine 60G of thrombin is explored with reference to the crystal structure of inhibitor enzyme complexes. A primary ion-dipole interaction between the terminal P2 side chain group and lysine 60G is evoked to explain the SAR in this series.

Thrombin inhibitors have been designed with the replacement of the strongly basic guanidine P1 pharmocophore with a group that exploits the lipophilicity of the S1 pocket. The approach has lead to the discovery of potent thrombin inhibitors demonstrating good intra-duodenal absorption.

The chemical optimisation of CGH1668 1 is described employing an in vivo model of absorption to determine the influence on bioavailability of single point modifications to five key molecular templates. The discovery of an orally bioavailable and selective thrombin inhibitor, 24, highlights the utility of this approach.

A technically simple model of arterial thrombosis in the rat, induced by a crush injury to the dorsal aorta is described. The mechanical injury to the artery caused deep medial injury and the formation of a platelet-rich thrombus with associated fibrin formation which was assessed both radiometrically and morphometrically. No significant inclusion of erythrocytes was noted in the thrombus. Administration of the platelet inhibitors aspirin, BM 13505 (a thromboxane receptor antagonist) or CGS 12970 (a thromboxane synthase inhibitor) reduced the extent of platelet deposition on the injured vessel, but no decrease in fibrin(ogen) was observed. In contrast, infusion of prostacyclin resulted in reductions in both these components of the thrombus. In studies involving inhibition of thrombin activity, the direct thrombin inhibitor CGP 39393 (recombinant desulphatohirudin) inhibited both the platelet and fibrin(ogen) deposition. The indirect thrombin inhibitors were less effective; unfractionated heparin and low-molecular-weight heparin inhibited both platelet and fibrin(ogen) deposition but only at doses which rendered the blood uncoagulable, as evaluated by the activated partial thromboplastin time. Dermatan sulphate only inhibited platelet deposition. The results suggest that thrombin plays a key role in the initiation of thrombus formation in this experimental model. The agonist prostaglandins (PGG2, PGH2, and TXA2) would appear to have a supporting role in the platelet deposition onto the thrombotic surface but do not have a role to play with respect to fibrin(ogen) deposition.

SummaryThe effects of the newly available biotechnology product, recombinant desulphatohirudin (CGP 39393) have been investigated in rats. This highly potent and selective thrombin inhibitor exhibited marked anticoagulant properties with controllable titration of anticoagulant effect, as measured by activated partial thromboplastin time (APTT), up to nearly four times control values. Furthermore, CGP 39393 exhibited impressive antithrombotic activity in vivo. In an arteriovenous shunt model of thrombus formation on a cotton-thread, the compound was capable of complete inhibition of thrombus development (ED50 = 0.3 mg/kg i.v. and 1.0 mg/kg s.c.). Venous stasis thrombosis was also highly susceptible to inhibition by CGP 39393 (ED50 = 0.01 mg/kg i.v. and 0.45 mg/kg s.c.). Comparison of the anticoagulant and antithrombotic activities of the compound shows that potent antithrombotic effects (83-97% inhibition in the rat shunt model) are achieved within the generally acceptable range of anticoagulation. These results suggest a clear potential for this new agent in the clinical treatment of thrombotic disease.

1. 1. Guinea pig platelet aggregation and ATP secretion induced by collagen and platelet-activating factor (PAF-acether) has been compared using a lumiaggregometer. 2. 2. Dose response curves for collagen-induced platelet aggregation occurred at slightly lower collagen concentrations than those for ATP secretion. In contrast, when PAF acether was the agonist, ATP secretion only occurred at agonist concentrations which induced nearly maximal platelet aggregation rate. 3. 3. Phenylbutazone, sulphinpyrazone and its metabolites inhibited both the aggregation and secretion simultaneously when this was induced by collagen with the rank potency order G 25671> G 31442 > phenylbutazone > sulphinpyrazone. As expected this parallels their potency as inhibitors of cyclooxygenase. 4. 4. The compounds only inhibited PAF acether-induced aggregation and ATP secretion at much higher concentrations. All of the sulphinpyrazone metabolites were equipotent in this case but phenylbutazone was ineffective. 5. 5. It is concluded that the phenyl group on the side chain of the sulphinpyrazone-like compounds could be important for inhibition of PAF-acether-induced platelet activation. 6. 6. The plasma concentrations of sulphinpyrazone and its metabolites required to inhibit PAF-acether-induced platelet activation are very high compared to those achieved in man. Thus inhibition of PAF acether-induced platelet aggregation is unlikely to be an important mechanism of action in man.

CGS 12970 is a potent selective inhibitor of human platelet thromboxane synthetase in vitro (IC50 = 12 nM). It is four orders of magnitude less potent as an inhibitor of sheep seminal vesicle cyclooxygenase, bovine aorta prostacyclin synthetase and human leucocyte 15-lipoxygenase. The compound inhibited collagen-induced thromboxane B2 production by human platelets in vitro without an effect on the accompanying platelet aggregation induced by collagen, ADP, platelet activating factor, thrombin, arachidonic acid or the prostaglandin mimetic, U 46619. Administration of CGS 12970 to rats inhibited collagen-induced thromboxane B2 production but had no effect on platelet aggregation ex vivo. It also had no effect on platelet aggregation induced by thrombin or on plasma clotting times. A single oral dose of 1 or 3 mg kg-1 to rabbits inhibited thromboxane B2 production in clotting blood ex vivo for 12 or 24 h respectively. CGS 12970 inhibited thromboxane B2 production in vivo induced by intravenous administration of collagen to rats or calcium ionophore to guinea-pigs. In both cases there was a concomitant elevation of immunoreactive 6-keto-prostaglandin F1 alpha but no effect on the induced thrombocytopenia. As with other thromboxane synthetase inhibitors, CGS 12970 prolonged tail bleeding time in the rat. However, CGS 12970 was not as potent as other thromboxane synthetase inhibitors in this test. In addition to these usual effects of thromboxane synthetase inhibitors, CGS 12970 inhibited the thrombocytopenia induced by the Forssman reaction or ADP administration. In these tests the effect of the compound was of short duration. 8 CGS 12970 had no effect on the thrombocytopenia associated with the Arthus reaction which distinguishes it from cyclo-oxygenase inhibitors. It also had no effect on thrombus formation on a cotton thread in an arteriovenous shunt in the rat.

In rabbits receiving a normal laboratory diet the platelet half-life was 40.4 +/- 2.5h (mean +/- S.D., n = 35). In animals fed the cholesterol-enriched diet for 12 weeks the platelet half-life was reduced to 31.6 +/- 3.6h (mean +/- S.D., n = 35). Treatment of cholesterol-fed animals with a single daily dose of CGS 12970 (a long acting inhibitor of thromboxane synthase) normalised the platelet half-life. Single daily doses of the relatively shorter acting thromboxane synthase inhibitors (CGS 13080 and dazoxiben) failed to correct the reduced platelet survival. However, twice daily dosing with dazoxiben was effective. The cyclooxygenase inhibitors, aspirin and sulphinpyrazone, failed to correct the reduced platelet survival.

When platelets are stimulated to aggregate and secrete by a sub-maximal concentration of an agonist, the platelets on the outside of an aggregate appear more degranulated than those on the inside (1) (fig. 1). In the example shown, aggregation of rabbit platelet-rich plasma (PRP) was induced by a sub-maximal concentration of collagen.