Advanced crystallisation methods for small organic molecules

Molecular materials based on small organic molecules often require advanced structural analysis, beyond the capability of spectroscopic techniques, to fully characterise them. In such cases, diffraction methods such as single crystal X-ray diffraction (SCXRD), are one of the most powerful tools available to researchers, providing molecular and structural elucidation at atomic level resolution, including absolute stereochemistry. However SCXRD, and related diffraction methods, are heavily dependent on the availability of suitable, high-quality crystals, thus crystallisation often becomes the major bottleneck in preparing samples. Following a summary of classical methods for the crystallisation of small organic molecules, this review will focus on a number of recently developed advanced methods for crystalline material sample preparation for SCXRD. This review will cover two main areas of modern small organic molecule crystallisation, namely the inclusion of molecules within host complexes (e.g., "crystalline sponge" and tetraaryladamantane based inclusion chaperones) and the use of high-throughput crystallisation, employing "under-oil" approaches (e.g., microbatch under-oil and ENaCt). Representative examples have been included for each technique, together with a discussion of their relative advantages and limitations to aid the reader in selecting the most appropriate technique to overcome a specific analytical challenge.

Chemical and structural data of (1,2,3-triazol-4-yl)pyridine-containing coordination compounds

The data presented in this paper are related to the research article entitled “Novel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-κN³]pyridine-κN})metal(II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)” (Conradie et al., 2018) [1]. This paper presents characterization and structural data of the 2-(1-(4-methyl-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligand (L²) (Tawfiq et al., 2014) [2] as well as seven dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-κN³]pyridine-κN})metal(II) coordination compounds, [M(L²)₂Cl₂], all containing the same ligand but coordinated to different metal ions. The data illustrate the shift in IR, UV/VIS, and NMR (for diamagnetic complexes) peaks when L is coordinated to the metals, as well as the influence of the different metals on the peak positions. Solid state structural data is presented for M = Ni and Zn, while density functional theory calculated energies, structures and optimized coordinates are provided for the lowest energy cis and trans conformations for L² as well as [M(L²)₂Cl₂] with M = Mn, Fe, Co, Ni, Cu, Zn and Cd.

Jahn–Teller distortion in 2-pyridyl-(1,2,3)-triazole-containing copper(ii) compounds

Octahedral copper(ii) compounds, containing two 2-pyridyl-(1,2,3)-triazole ligands as well as two Cl ions, exhibit elongation Jahn–Teller distortion.

[MIII2MII3] n+ trigonal bipyramidal cages based on diamagnetic and paramagnetic metalloligands

A family of five [MIII2MII3] n+ trigonal bipyramidal cages (MIII = Fe, Cr and Al; MII = Co, Zn and Pd; n = 0 for 1-3 and n = 6 for 4-5) of formulae [Fe2Co3L6Cl6] (1), [Fe2Zn3L6Br6] (2), [Cr2Zn3L6Br6] (3), [Cr2Pd3L6(dppp)3](OTf)6 (4) and [Al2Pd3L6(dppp)3](OTf)6 (5) (where HL is 1-(4-pyridyl)butane-1,3-dione and dppp is 1,3-bis(diphenylphosphino)propane) are reported. Neutral cages 1-3 were synthesised using the tritopic [MIIIL3] metalloligand in combination with the salts CoIICl2 and ZnIIBr2, which both act as tetrahedral linkers. The assembly of the cis-protected [PdII(dppp)(OTf)2] with [MIIIL3] afforded the anionic cages 4-5 of general formula [MIII2PdII3](OTf)6. The metallic skeleton of all cages describes a trigonal bipyramid with the MIII ions occupying the two axial sites and the MII ions sitting in the three equatorial positions. Direct current (DC) magnetic susceptibility, magnetisation and heat capacity measurements on 1 reveal weak antiferromagnetic exchange between the FeIII and CoII ions. EPR spectroscopy demonstrates that the distortion imposed on the {MO6} coordination sphere of [MIIIL3] by complexation in the {MIII2MII3} supramolecules results in a small, but measurable, increase of the zero field splitting at MIII. Complete active space self-consistent field (CASSCF) calculations on the three unique CoII sites of 1 suggest DCo ≈ -14 cm-1 and E/D ≈ 0.1, consistent with the magnetothermal and spectroscopic data.

Synthesis, conformation and antiproliferative activity of isothiazoloisoxazole 1,1-dioxides

Isothiazoles (I) reacted with 1,3-dipoles or NaN₃ to give cycloadducts (II) or thiazete (III). Thiazete (III) rearranged to give 1,2,3-oxathiazoline (IV).

[CrIII8MII6]n+ (MII = Cu, Co) face-centred, metallosupramolecular cubes

Heterometallic cubes, assembled in a modular fashion from a [CrL₃] metalloligand and simple M^II salts, display interesting encapsulation and magnetic behaviours.

Metal-organic fireworks: MOFs as integrated structural scaffolds for pyrotechnic materials

A new approach to formulating pyrotechnic materials is presented whereby constituent ingredients are bound together in a solid-state lattice. This reduces the batch inconsistencies arising from the traditional approach of combining powders by ensuring the key ingredients are 'mixed' in appropriate quantities and are in intimate contact. Further benefits of these types of material are increased safety levels as well as simpler logistics, storage and manufacture. A systematic series of new frameworks comprising fuel and oxidiser agents (group 1 and 2 metal nodes & terephthalic acid derivatives as linkers) has been synthesised and structurally characterised. These new materials have been assessed for pyrotechnic effect by calorimetry and burn tests. Results indicate that these materials exhibit the desired pyrotechnic material properties and the effect can be correlated to the dimensionality of the structure. A new approach to formulating pyrotechnic materials is proposed whereby constituent ingredients are bound together in a solid-state lattice. A series of Metal-organic framework frameworks comprising fuel and oxidiser agents exhibits the desired properties of a pyrotechnic material and this effect is correlated to the dimensionality of the structure.

Isolation and structural determination of non-racemic tertiary cathinone derivatives

In this paper the dynamic resolution of racemic tertiary cathinones is demonstrated through co-crystallization with enantiopure aromatic tartaric acids.

Stereospecific generation of homochiral helices in coordination polymers built from enantiopure binaphthyl-based ligands

The novel enantiopure spacer 2,2′-dimethoxy-1,1′-binaphthyl-3,3′-bis(4-pyridyl-amido) has been designed to prepare helical coordination polymers here investigated by means of experimental and theoretical data.

Pharmaceutical co-crystals – are we there yet?

Progression from drug to co-crystal to medicine.

A truncated [MnIII12] tetrahedron from oxime-based [MnIII3O] building blocks

The use of the novel pro-ligand H₄L combining the complimentary phenolic oxime and diethanolamine moieties in one organic framework, results in the formation of the first example of a [Mn^III₁₂] truncated tetrahedron.

Relationships between the racemic structures of substituted mandelic acids containing 8- and 10-membered hydrogen bonded dimer rings

The structures of 27 monosubstituted mandelic acids, including several of their polymorphs, plus unsubstituted mandelic acid itself (two polymorphs) are investigated for structural similarity.

Airway mucus: composition and regulation of its secretion by neuropeptides in vitro

Human and canine airway mucosa in vitro synthesizes and secretes mucus glycoprotein, proteoglycans and lipids which can be separated by density gradient ultracentrifugation in caesium bromide. In secretions from unstimulated explants, the small amount of mucus glycoprotein present is found in association with proteoglycans. 'Free' mucus glycoprotein of typical buoyant density is present only after stimulation of submucosal gland secretion by methacholine. Lipids are synthesized, at least in part, by the airway mucosa and occur in explant secretions as a viscoelastic gel, suggesting that they significantly influence the rheological properties of airway mucus. In addition to cholinergic and adrenergic secretomotor neurons, the airway mucosa is innervated by peptidergic fibres containing immunoreactivity to vasoactive intestinal peptide (VIP) and substance P (SP). In explants of non-bronchitic human airway, VIP inhibits baseline glycoprotein and lysozyme secretion; in canine airway mucosa, by contrast, VIP is a weak partial secretory agonist. SP is the most potent agonist of canine airway glycoprotein release described to date and appears to evoke secretion by a direct action on a stereospecific SP receptor rather than by inducing release of other endogenous secretagogues. VIP and SP have little effect on glycoprotein discharge by mucous and serous cells of the submucosal gland; SP appears to induce secretion by causing contraction of submucosal gland ducts. This may represent the most rapid way for delivering mucus into the airway in response to injury or irritation of airway epithelium.

A prospective randomised controlled trial of nutritional supplementation in malnourished elderly in the community: clinical and health economic outcomes

BACKGROUND & AIMS

Malnutrition is common in sick elderly people on admission to hospital and in the community. We conducted a randomised controlled trial to determine if nutritional supplementation after discharge from hospital improved nutritional status and functional outcomes, or reduced health-care costs.

METHODS

Elderly malnourished subjects were randomised to 8 weeks of supplementation or no supplementation post discharge, and followed up for 24 weeks. Weight, body mass index, anthropometrics, handgrip strength, quality of life and requirements for health-care professionals' services and social services were measured throughout the study.

RESULTS

Nutritional status improved significantly from baseline to week 24 in the intervention group (P<0.05), but not in the control group. There was no significant difference in nutritional status between groups at week 24. Handgrip strength improved significantly in the intervention group during supplementation, and was significantly different from that of the control group at week 8, but decreased thereafter. There was no significant difference in quality of life or health economic outcomes between groups at week 24.

CONCLUSIONS

In already malnourished elderly subjects, it may be too late to expect to improve function or quality of life or to reduce health-care costs simply by providing nutritional supplements after hospitalisation. Prevention is key. All elderly patients should be nutritionally assessed as part of their routine care, and appropriate intervention initiated early.

Multidentate Lewis acids: synthesis, structure and mode of action of a redox-based fluoride ion sensor

The mode of action of the bidentate bis(boronate) Lewis acid 2 as a fluoride ion sensor is shown to involve selective anion binding together with an electrochemical response.

2-amidopyrroles and 2,5-diamidopyrroles as simple anion binding agents

Four new 2-amidopyrroles and 2,5-diamidopyrroles have been synthesized and their anion complexation properties investigated. The crystal structures of these receptors have been elucidated and reveal hydrogen bonding in the solid state leading to dimer and network formation. Selectivity for oxo-anions has been demonstrated by (1)H NMR titration techniques.

Patterns of prescribing of nutritional supplements in the United Kingdom

BACKGROUND AND AIMS

A large number of prescriptions are issued for nutritional supplements under British National Formulary classifications 9.4.1 (foods for special diets) and 9.4.2 (enteral feeds), but little is known about the characteristics of the patients who receive them. We used the General Practice Research Database to examine patterns of prescribing of these supplements.

METHODS

We selected patients who had been prescribed supplements under classifications 9.4.1 and 9.4.2 during 1996-1997. Descriptive statistics were used to examine how prescribing varied.

RESULTS

28644 patients received prescriptions during 1996-1997. Among the 27413 (96%) patients prescribed supplements for oral use, 14750 received supplements for enteral nutrition alone, 8122 received supplements for special diets alone and 4541 had both types of supplement. 51% of patients receiving supplements for special diets were <18 years. The commonest diagnoses among such children were milk intolerance (24%) and malnutrition (17%). 94% of patients receiving supplements for enteral nutrition were adult, 52% of whom had cancer or cardiovascular disease. Only 4% of patients had weight and height recorded prior to first prescription.

CONCLUSIONS

The GPRD provides valuable information on the characteristics of patients prescribed nutritional supplements. But because only limited data are available on their nutritional status prior to supplementation, it is hard to assess whether general practitioners are prescribing these supplements appropriately.

trans-4-[(4-dimethylaminophenyl)-iminomethyl]-N-methyllpyridinium para-toluenesulfonate

In the title compound, C15H18N3+*C7H7O3S-, the phenylene and pyridyl rings are somewhat twisted with respect to each other, forming a dihedral angle of 23.49 (6) degrees. The compound contains a dipolar chromophoric cation, but crystallizes in the centrosymmetric space group P2(1)/n and is thus not expected to display quadratic non-linear optical effects.

Prevalence of malnutrition on admission to four hospitals in England. The Malnutrition Prevalence Group

AIMS

The primary objective was to estimate prevalence of malnutrition on admission to four hospitals. Secondary objectives included assessing the relationship between nutritional status and length of hospital stay, numbers of new prescriptions, new infections and disease severity.

METHODS

We entered eligible patients according to predefined quotas for elective and emergency admissions to 23 specialties. We measured height, weight, Body Mass Index and anthropometrics, and recorded history of unintentional weight loss. Patients who had lost > or = 10% of their body weight, had a Body Mass Index <20, or had a Body Mass Index <20 with one anthropometric measurement <15th centile were considered malnourished.

RESULTS

Of 1611 eligible patients, 761 did not participate; 269 were too ill; 256 could not be weighed; and 236 refused consent. Eight hundred and fifty were subsequently evaluated. Prevalence of malnutrition on admission was 20%. Length of stay, new prescriptions and infections and disease severity were significantly higher in the malnourished.

CONCLUSIONS

One patient in every five admitted to hospital is malnourished. Although this figure is unacceptably high, it may underestimate true prevalence. Malnutrition was associated with increased length of stay, new prescriptions and infections. Malnutrition may also have contributed to disease severity.

tert-Butyl 2-[2-(ethoxycarbothioylamino)-3-pyridyloxy]acetate andtert-butyl 2-(3-thioxopyrido[2,1-c][1,2,4]thiadiazol-8-yloxy)acetate

Compounds (I), C(14)H(20)N(2)O(4)S, and (II), C(12)H(14)N(2)O(3)S(2), are two minor products of the same reaction. Both structures contain identical ester functionalities in similar orientations. Both independent molecules of (I) contain an ethoxycarbothioylamine moiety, whilst (II) possesses a novel exocyclic thione system fused with a pyridine ring.

Charge densities from high-resolution synchrotron X-ray diffraction experiments

The combination of intense X-ray sources, especially synchrotron radiation, with area-detector technology has accomplished an enormous advance in the experimental conditions available for charge-density analysis by single-crystal high-resolution X-ray diffraction. Such experiments can now be carried out in a time measured in hours rather than weeks. Some features of these experiments are examined and preliminary results are reported for charge-density studies of 2-hydroxy-5-nitrobenzaldehyde N-cyclohexylimine (1), octakis(m-tolylthio)naphthalene (2), and 7-fluoro-4-styrylcoumarin (3). Weak interactions in crystals of (1) and (3) are found to have similar charge-density characteristics. Cages in the crystal lattice of (2) have a complex charge distribution.

A family of polynuclear cobalt and nickel complexes stabilised by 2-pyridonate and carboxylate ligands

The synthesis and structural characterisation of a series of cobalt and nickel cages are reported. Eight of these structures contain a [M10(mu3-OH)6(eta2, mu3-xhp),(eta2, mu2-O2CR)6]2+ core (where M = Co or Ni; xhp = 6-chloro- or 6-methyl-2-pyridonate: R = Me, Ph, CHMe2, CH2Cl, CHPh2 or CMe3), where the ten metal atoms describe a centred-tricapped-trigonal prism (ttp). The cage contains six hydroxide ligands around the central metal, and the exterior is coated with pyridonate and carboxylate ligands. For four of the cages additional metal centres are found attached to the upper and/or lower triangular faces of the trigonal prism, generating dodeca- and undecanuclear cages. Three further cages are reported that contain a metal core based on an incomplete centred-tetraicosahedron. These cages involve trimethylacetate as a ligand in company with either 6-methyl-2-pyridonate or 6-chloro-2-pyridonate. Comparison of these latter structures with the trigonal prisms reveal that they can be described as a pentacapped-trigonal prism missing one edge. Magnetic studies of three of the nickel cages with trigonal prismatic cores show spin ground states of S = 8, 4 and 2 for Ni12, Ni11 and Ni10 cages, respectively.

Outcomes of undernutrition in patients in the community with cancer or cardiovascular disease

Public health concern has tended to focus on the dangers of obesity, but there is evidence that undernutrition may also pose a risk to physical and mental well-being, particularly in those who are already ill. Using the General Practice Research Database (see office for Population Censuses and Surveys, 1995), we followed up 10,128 men and women aged 18 years and over who had been diagnosed with cancer or cardiovascular disease to examine whether nutritional status, as indicated by BMI, affected rates of use of health care resources and mortality. In both diagnostic groups, patients with a BMI below 20 kg/m2 had higher rates of consultation with GP, higher rates of prescription and higher death rates during the follow-up period compared with those with a BMI of 20-< 25 kg/m2. In men and women with cardiovascular disease, poor nutritional status was associated with a sharply increased risk of hospital admission. Patients whose BMI was 30-< 40 kg/m2 also tended to have increased rates of GP consultation and prescription, and if they were under the age of 65 years, they had an increased risk of death. The results of the present study suggest that in men and women with cancer or cardiovascular disease, even minor degrees of undernutrition are associated with a marked increase in morbidity and mortality.

Effect of nutritional status on use of health care resources by patients with chronic disease living in the community

The prevalence of malnutrition in patients with chronic disease living in the community in the UK is around 8%. Whether such patients experience greater morbidity and mortality or make increased use of health care resources is unknown. The aim of this study was to investigate how the use of health care resources by patients with chronic disorders of the respiratory, gastrointestinal and neurological systems varied by nutritional status. We used longitudinal data, collected since 1987, which formed part of the General Practice Research Database in the UK. Subjects were 11 357 men and women aged 18 years or over. Main outcomes were consultation rates in general practice, prescription rates, hospital referral rates, hospital admission rates and mortality. Consultation and prescription rates were lowest amongst patients whose body mass index (BMI) was between 20 and 25. Rates were higher in patients whose BMI was below 20, or 25 and above. There was no statistically significant relation between rate of hospital outpatient referral and nutritional status, but both hospital admission rate and mortality were greatest in those people whose BMIs were below 20 and declined as BMIs increased. In patients with differential use of health care resources in both primary care and hospital practice, and with differences in mortality.

Comparison of clarithromycin suspension and amoxycillin syrup for the treatment of children with pharyngitis and/or tonsillitis

Twenty-three general practices in the UK randomised 229 paediatric patients (aged 1-12 years, body weight > 8 kg) with clinical evidence suggestive of streptococcal tonsillitis and/or pharyngitis in this physician-blind study. Patients received either clarithromycin suspension (7.5 mg/kg twice daily) or amoxycillin syrup (125 mg/kg three times daily body weight < 25 kg, or 250 mg/kg three times daily body weight 25 kg) for 7 days and were followed up 3-8 days post treatment and 21-28 days later. Clinical and microbiological assessments were made at each visit. A total of 189 patients (98 on clarithromycin and 91 on amoxycillin) were clinically evaluable. At the post-treatment visit, clinical success rates were high and comparable: 98% on clarithromycin and 97% on amoxycillin. Streptococcus pyogenes was eradicated in 88% of clarithromycin patients and 86% of amoxycillin patients. Both treatments were well tolerated. In conclusion, clarithromycin suspension was as safe and at least as effective as amoxycillin syrup for the treatment of pharyngitis and/or tonsillitis in children, and would be a suitable alternative therapy.

A comparative study of clarithromycin and amoxycillin suspensions in the treatment of pediatric patients with acute otitis media

This phase III, single-blind, randomized, multicentre clinical trial compared the safety and efficacy of clarithromycin and amoxycillin in the treatment of otitis media in pediatric patients. Two hundred and fifty-nine patients aged 1-12 were prescribed suspensions of clarithromycin (132 patients) or amoxycillin (127 patients). Both suspensions were prescribed at a dose of 125 mg for children weighing less that 25 kg or at 250 mg for children weighing more than 25 kg, but three doses of amoxycillin per day were given, while only two doses clarithromycin per day were required. Each drug was administered for approximately 5 days. Clinical evaluations were performed pre-treatment (Study Day 1), at the end of treatment (Study Days 6-9), and post-treatment (Study Days 28-32). At the end of treatment, 91 out of 114 evaluable patients (80%) had clinical cures with clarithromycin, while 71 out of 105 evaluable patients (68%) had clinical cures with amoxycillin (p = 0.057). Clinical success rates were 96% for both treatments (110/114, clarithromycin; 101/105 amoxycillin). Adverse events related to the study medications occurred in four of 132 patients receiving clarithromycin (3%) and eight out of 127 subjects receiving amoxycillin (6%). Three patients discontinued treatment due to adverse events, all three receiving amoxycillin. At the doses administered, clarithromycin given twice-daily was as safe and effective as given three-times-daily in the treatment of acute otitis media in pediatric patients.

A single-blind, randomised, comparative study of clarithromycin and amoxycillin suspensions in the treatment of children with lower respiratory tract infections

One hundred and forty-five children with signs and symptoms of lower respiratory tract infections were entered into this multicentre, General Practice, investigator-blind study, designed to demonstrate equivalent efficacy between clarithromycin and amoxycillin suspensions. Seventy one children were randomised to treatment with clarithromycin suspension 7.5 mg/kg bodyweight twice daily and 74 to treatment with amoxycillin suspension 125 mg (bodyweight < 25 kg) or 250 mg (bodyweight > or = 25 kg) three times a day according to bodyweight. Duration of therapy was 5-10 days as determined by the investigator. Clinical evaluations were performed pretreatment, during treatment and post-treatment within 72 hours of cessation of therapy. Fifty two children in the clarithromycin group and 57 in the amoxycillin group were clinically evaluable. Both study medications were effective and there were no significant differences between the groups with respect to clinical cure rate (60% for clarithromycin and 63% for amoxycillin), clinical success rate (cure plus improvement, 96% for clarithromycin and 95% for amoxycillin) or rate of resolution of clinical signs and symptoms in clinically evaluable patients. The intention to treat analysis for all patients entered similarly showed no significant differences in efficacy. The two treatment groups did not differ significantly with respect to incidence or severity of adverse events which were generally mild and associated with the gastrointestinal system. Therapy was withdrawn because of adverse events in three children on clarithromycin and one on amoxycillin. Bacteriological cure rates could not be determined because of an insufficient number of evaluable pre-treatment sputum samples.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of the effects of the selective peripheral alpha 1-blocker terazosin with the selective beta 1-blocker atenolol on blood pressure, exercise performance and the lipid profile in mild-to-moderate essential hypertension

The effects of six weeks of treatment with the selective peripheral alpha 1-adrenoceptor blocker terazosin, or the selective beta 1-adrenoceptor blocker atenolol on blood pressure, exercise performance and blood lipid profile were compared in a single-blind, randomized, crossover study of 17 patients with mild-to-moderate essential hypertension. Although both drugs significantly reduced blood pressure at rest, atenolol caused a larger fall in supine blood pressure (11/11 and 7.5/7.0 mmHg, atenolol and terazosin, respectively; p < 0.001). Both treatments controlled the pressor response to exercise, although a greater reduction in diastolic blood pressure was observed at the end of exercise on terazosin (74.0 +/- 5.7 and 91.6 +/- 4.0 mmHg, terazosin and atenolol, respectively; p < 0.01). Alpha 1-blocker therapy was not associated with any measurable improvement or deterioration in cardiopulmonary performance and exercise duration. Unlike atenolol, terazosin therapy had the potentially beneficial effect of reducing serum total cholesterol levels and increasing the high-density lipoprotein-cholesterol/low-density lipoprotein-cholesterol ratio.

Effect of carbohydrate rich versus fat rich loads on gas exchange and walking performance in patients with chronic obstructive lung disease

BACKGROUND

High calorie intakes, especially as carbohydrate, increase carbon dioxide production (VCO2) and may precipitate respiratory failure in patients with severe pulmonary disease. Energy obtained from fat results in less carbon dioxide and thus may permit a reduced level of alveolar ventilation for any given arterial blood carbon dioxide tension (PaCO2).

METHODS

Ten patients with stable severe chronic obstructive lung disease underwent a six minute walk before and 45 minutes after taking 920 kcal of a fat rich drink, an isocalorific amount of a carbohydrate rich drink, and an equal volume of a non-calorific control liquid on three separate days, in a double blind randomised crossover study. Borg scores of the perceived effort to breathe were measured at the beginning and end of each six minute walk. Minute ventilation (VE2), VCO2, oxygen consumption (VO2), respiratory quotient (RQ), arterial blood gas tensions, and lung function were measured before and 30 minutes after each test drink.

RESULTS

Baseline measurements were similar on all three test days and the non-calorific control drink resulted in no changes in any of the measured variables. The carbohydrate rich drink resulted in significantly greater increases in VE, VCO2, VO2, RQ, PaCO2, and Borg score and a greater fall in the distance walked in six minutes than the fat rich drink (mean fall after carbohydrate rich drink 17 m v 3 m after fat rich drink and the non-calorific control). The increase in VCO2 correlated significantly with the decrease in six minute walking distance and the increase in Borg score after the carbohydrate rich drink. The only significant change after the fat rich drink when compared with the non-calorific control was an increase in VCO2.

CONCLUSIONS

Comparatively small changes in the carbohydrate and fat constitution of meals can have a significant effect on VCO2, exercise tolerance, and breathlessness in patients with chronic obstructive lung disease.

A multicentre, hospital study of the efficacy and safety of terazosin and its effects on the plasma cholesterol levels of patients with essential hypertension

The safety, efficacy and the effect on the plasma total cholesterol of once-daily terazosin hydrochloride administered either as monotherapy or in combination with other antihypertensive therapy were evaluated in patients with mild-moderate uncontrolled essential hypertension in this U.K., open, multicentre hospital, 3-month study. Patients initially received 1 mg of terazosin as monotherapy or in addition to their current antihypertensive therapy followed by dose titration, if necessary, to a maximum of 10 mg over the first 6 weeks depending upon blood pressure control. Patients then continued treatment for a further 6 weeks on their optimum dosage. There were highly significant mean reductions in systolic and diastolic blood pressures at the end of 12 weeks for 439 patients of 18.5 and 14.0 mmHg (P less than 0.001), respectively, and were similar to the reductions shown when subgrouping the patients into either those 197 patients who were treated with terazosin as monotherapy (17.6/13.7 mmHg, P less than 0.001) or those 242 patients treated with terazosin in combination with other antihypertensive agents (19.3/14.2 mmHg, P less than 0.001). In addition, in a sub-group of 132 patients who had their mean total cholesterol measured at the end of 12 weeks' treatment, there was a significant reduction of -0.4 mmol/l (P less than 0.01). A similar significant mean reduction for total cholesterol was also shown when this subgroup was divided into those 50 patients who were treated with terazosin as monotherapy (-0.56 mmol/l, P less than 0.01), but not for those 82 patients treated with terazosin in combination with other antihypertensive agents (-0.3 mmol/l, P greater than 0.05 less than 0.1). No serious toxicity or safety problems were observed. Once daily administration of terazosin, either as monotherapy or in combination with other antihypertensive agents, proved to be safe and effective in reducing the blood pressure of patients with uncontrolled mild-moderate essential hypertension and favourably reduced the total plasma cholesterol level.