Did the introduction of general practice fundholding change patterns of emergency admission to hospital?

OBJECTIVES

To test the hypothesis that the introduction of general practice fundholding was associated with a change in the proportion of emergency admissions to hospital.

METHODS

Before and after natural experiment with control group. The experimental group was first-wave fundholding general practices in the South Western Regional Health Authority, the control group was all practices that remained non-fundholding as of April 1993. Data were collected on episodes of care in hospitals in the South Western region involving cholecystectomy, hernia repair, intervertebral disc operation and prostatectomy. The additional impact of fundholding status on any underlying changes in proportions of emergency admissions was examined using multiple logistic regression.

RESULTS

There was no evidence of an interaction between fundholding status and before/after time period. Odds ratios and confidence intervals for the interaction of general practice fundholding status and time were: prostatectomy 1.02 (0.77 to 1.34); hernia repair 0.94 (0.7 to 1.24); intervertebral disk operations 1.67 (0.8 to 3.47); prostatectomy 0.94 (0.69 to 1.27).

CONCLUSIONS

The results provide no evidence that, in the first 2 years of the scheme, fundholding had an impact on the proportion of emergency admissions to hospital.

Attitude of emergency department patients toward HIV-infected health care workers

A telephone survey of a random sample of adult emergency department (ED) patients was conducted at a university health science center. The purpose of the study was to determine the opinion of ED patients concerning the risk of human immunodeficiency virus (HIV) transmission and their willingness to be treated by HIV-infected physicians and nurses. Surveys from 107 ED patients were compiled and available for analysis. Ninety percent of the respondents were tolerant of an HIV-infected physician or nurse (HIV + HCW)performing noninvasive procedures. Fifty percent were tolerant of an HIV + HCW performing invasive procedures. Twenty-six percent of the patients said they would leave the department rather than be treated by an HIV + HCW. Patients older than 50 years were less tolerant (P = .004) and more likely to leave the ED (P = .001).

Transferred nuclear Overhauser enhancement (NOE) and rotating-frame NOE experiments reflect the size of the bound segment of the Forssman pentasaccharide in the binding site of Dolichos biflorus lectin

A complex between the Forssman pentasaccharide alpha-D-GalNAc-(1-->3)-beta-D-GalNAc-(1-->3)-alpha-D-Gal-(1-->4)-beta-D- Gal-(1-->4)-D-Glc and the seed lectin from Dolichos biflorus was studied using transfer-NOESY and transfer rotating frame NOE spectroscopy (ROESY) experiments. The evolution of transferred NOEs and ROEs as a function of the pentasaccharide/lectin ratio was different for the non-reducing disaccharide moiety alpha-D-GalNAc-(1-->3)-beta-D-GalNac compared to the rest of the molecule, which reflects distinct relaxation properties and effects of exchange broadening of the corresponding ligand resonances. Significantly, several intermolecular transferred NOEs were observed between protons of the nonreducing disaccharide moiety alpha-D-GalNAc-(1-->3)-beta-D-GalNAc and aliphatic as well as aromatic amino acid side chain protons in the binding pocket of the lectin. It is concluded that the non-reducing disaccharide fragment is buried in the lectin-binding pocket, whereas the reducing trisaccharide portion alpha-D-Gal-(1-->4)-beta-D-Gal-(1-->4)-D-Glc has no immediate contacts with the protein. The experimental transfer NOE data were qualitatively compared to theoretical proton-proton distances from a model that was based on a previous homology modeling study of a complex between the disaccharide fragment alpha-D-GalNAc-(1-->3)-beta-D-GalNAc and D. biflorus lectin. It was found that all intermolecular transferred NOEs matched short interatomic distances between ligand protons and aliphatic or aromatic amino acid side chain protons predicted by the theoretical model.

Serum and urine albumin: a progress report on their measurement and clinical significance

For about 25 years, bromcresol green and bromcresol purple have been the basis for most of the measurements of serum albumin in the US and perhaps in the world. The longevity of the methods is due to their being simple, sensitive, specific, inexpensive and relatively free from interferences. The lack of change in the serum albumin methodology is balanced by two important developments. First, the recognition of the importance of serum albumin in the maintenance of good health, and the association of decreased concentrations with increased risk of morbidity and mortality. Second, the association of albuminuria with diabetic nephropathy, which without medical intervention could lead to end-stage renal disease. The development of accurate and precise methods for urinary albumin has provided a tool to physicians to extend the length and improve the quality of life of many diabetic individuals.

Conformational analysis of biantennary glycans and molecular modeling of their complexes with lentil lectin

Some mannose-binding legume lectins show higher affinity for fucosylated glycans than for glycans without fucose. These lectins possess a secondary binding site. Owing to the possibility of additional fucose binding, oligosaccharides adopt different conformations depending on whether they contain fucose or not. To study these conformational differences, complexes of fucosylated and unfucosylated glycans with Lens culinaris lectin have been modeled. Starting points were X-ray structures of lentil lectin and complexes of the homologous Lathyrus ochrus lectin. The SYBYL molecular modeling package with the TRIPOS force field was used. Two different models were built, displaying in both a network of hydrogen bonds between the saccharide and the binding site. Furthermore, to compare the free and bound ligand, conformational analysis in the free state has been performed. A complete analysis of all possible disaccharide fragments has been performed using the MM3 force field. A CICADA analysis employing the same force field was carried out to study the complete oligosaccharide. Low-energy conformers found by CICADA were clustered in conformational families and analyzed in terms of flexibility and rotational barriers. All values of glycosidic torsion angles are in the range as calculated by MM3 for the disaccharides.

Antithrombotic action of the kava pyrone (+)-kavain prepared from Piper methysticum on human platelets

(+)-Kavain, a 4-methoxy-alpha-pyrone prepared from Piper methysticum Forst. (Piperaceae), was investigated regarding its assumed antithrombotic action on human platelets which was deduced from its ability to suppress arachidonic acid (AA)-induced aggregation, exocytosis of ATP, and inhibition of cyclooxygenase (COX) and thromboxane synthase (TXS) activity, the latter two effects being estimated from the generation of prostaglandin E2 (PGE2) and thromboxane A2 (TXA2), respectively. Exogenously applied AA (100 mumol/l) provoked a 90% aggregation of platelets, the release of 14 pmol ATP, and the formation of either 220 pg TXA2 or 43 pg PGE2, each parameter being related to 10(6) platelets. An application of (+)-kavain 5 min before AA, dose-dependently diminished aggregation, ATP-release, and the synthesis of TXA2 and PGE2 with IC50 values of 78, 115, 71, and 86 mumol/l, respectively. The similarity of the IC50 values suggest an inhibition of COX by (+)-kavain as primary target, thus suppressing the generation of TXA2 which induces aggregation of platelets and exocytosis of ATP by its binding on TXA2-receptors.

Quasispecies analysis in hepatitis C virus infection by fluorescent single strand conformation polymorphism

Hepatitis C virus (HCV) results frequently in chronic hepatitis and its sequelae liver cirrhosis and hepatocellular carcinoma. Interferon-alpha is at present the most effective treatment, resulting in a sustained response in about 20-25% of patients. HCV genotype, titer and quasispecies determine the success of treatment. In this study, fluorescent single strand conformation polymorphism (f-SSCP) was evaluated for the analysis of HCV quasispecies. Two sera from a chronically HCV-infected patient, obtained 6 years apart, were examined. The hypervariable region I (HVRI) of the HCV genome was amplified by reverse transcription and PCR. The PCR products were cloned and sequenced or fluorescein-labeled and subjected to f-SSCP. Both methods demonstrated a single HCV species in the early serum and multiple quasispecies in the late serum. Single clones of the heterogeneous virus population were used to optimize conditions for f-SSCP. The most important factors were the gel temperature and virus titer. At the optimal running temperature one base exchange in 218 bases was detectable. Repeat extractions and amplifications gave identical results. Dilution of the serum containing multiple quasispecies resulted in a 'loss' of species. Provided the running temperature is optimal and virus titer is sufficient, f-SSCP is shown to be fast and reliable for HCV quasispecies analysis.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part VI

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part VI of this six-part series focuses on atherectomy and restenosis tissue obtained by atherectomy procedures.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part V

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed "remodeling." Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (< or = 1 year) and old (> 1 year) saphenous vein bypass grafts.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part IV

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part IV of this six-part series focuses on morphologic correlates of coronary angiographic patterns of remodeling after balloon angioplasty and discusses effects of angioplasty on adjacent, nondilated vessels.

Kavain inhibits non-stereospecifically veratridine-activated Na+ channels

The action of the natural kava pyrone, (+)-kavain, and its synthetic racemate, (+/-)-kavain, on voltage-dependent Na+ channels was investigated, while considering their stereospecific properties, on veratridine-induced increases in cytosolic free Na+ and Ca2+ ([Na+]i, [Ca2+]i) and the release of endogenous glutamate from cerebrocortical synaptosomes. Both compounds dose-dependently suppressed the veratridine-induced increase in [Na+]i, [Ca2+]i and glutamate release with IC50 values (+/- S.D.) of 71 +/- 22, 72 +/- 7, 120 +/- 37 micromol/l (+)-kavain and 77 +/- 21, 90 +/- 14, 92 +/- 23 micromol/l (+/-)-kavain, respectively. As judged from the dose-dependency, IC50 values, velocity and time course of action, both kava pyrones were equally effective suggesting a non-stereospecific inhibition of veratridine-activated Na+ channels.

Heart and respiratory rates and their significance for convective oxygen transport rates in the smallest mammal, the Etruscan shrew Suncus etruscus

Heart and respiratory rates of the smallest mammal (mean adult body mass 2g), the Etruscan shrew Suncus etruscus, were determined at rest and under stress conditions. Heart rate was obtained from electrocardiograms (ECGs), recorded via foot electrodes. The mean +/- S.D. heart rate of resting animals (ambient temperature 22 degrees C) was 835 +/- 107 min-1, the mean maximal rate amounted to 1093 +/- 235 min-1. The highest single value recorded was 1511 min-1, which is the highest heart rate reported so far for an endotherm. The respiratory rate was also obtained from ECG recordings, which showed the electrical activity of the breathing muscles during inhalation, and additionally by recording the movements of the thoracic wall with a laser autofocus system. The mean resting respiratory rate was 661 +/- 93 min-1, the mean maximal rate was 758 +/- 109 min-1 and the highest single value recorded was 894 min-1. At 22 degrees C, the specific oxygen consumption rate is 67 times higher in resting S. etruscus than in resting humans. Under these conditions, the respiratory rate of the shrew is 47 times higher but the heart rate only 12 times higher than in man. Therefore, to achieve an adequate circulatory oxygen transport rate, the product of relative stroke volume and arterio-venous O2 difference has to be 5.6 times higher in the shrew than in man, whereas for an appropriate ventilatory oxygen transport rate the product of relative tidal volume and oxygen extraction has to be only 1.4 times higher in this small insectivore than in man. The maximal possible oxygen transport rates of the ventilatory and the circulatory system have been estimated and compared with the diffusional transport capacity of the lung. These rates amount to approximately 1000 ml O2 kg-1 min-1. According to our results and data in the literature, an aerobic scope of 7-10 seems to be realistic for the Etruscan shrew.

Anticonvulsive action of (+/-)-kavain estimated from its properties on stimulated synaptosomes and Na+ channel receptor sites

Kava pyrones are constituents of the intoxicating pepper (Piper methysticum Forst), which has been shown to be anticonvulsive. The question of how the excitability of neurons is affected was investigated by determining the interaction of (+/-)-kavain with epitopes (site 1, site 2) of voltage-dependent Na+ channels and the action of (+/-)-kavain on 4-aminopyridine-stimulated synaptosomes as model of repetitive firing neurons. [3H]Saxitoxin and [3H]batrachotoxin were used for radioligand-binding assays performed with synaptosomal membranes. Gultamate released from 4-aminopyridine-stimulated cerebrocortical synaptosomes and the cytosolic concentrations of Na+ and Ca2+ ([Na+]i, [Ca+]i) were detected fluorometrically by using an enzyme-linked assay, sodium-binding benzofuranisophthalate (SBFI) and Fura-2, respectively. (+/-)-Kavain failed to compete with [3H]saxitoxin up to 400 mumol/l but dose-dependently suppressed binding of [3H]batrachotoxin with an IC50 value of 88 mumol/l (Ki = 72 mumol/l) although displacement of [3H]batrachotoxin was restricted to 33% of control at 400 mumol/l (+/-)-kavain. In stimulated synaptosomes, 5 mmol/l 4-aminopyridine provoked an increase in [Na+]i and [Ca2+]i by 9 mmol/l Na+ and 235 nmol/l Ca2+. Comparable to the reduction in [3H]batrachotoxin binding, 400 mumol/l (+/-)-kavain suppressed the increase in [Na+]i and [Ca2+]i to 38 and 29% of control, respectively. Consistent with the increase in [Na+]i and [Ca2+]i, 5 mmol/l 4-aminopyridine provoked glutamate release (rate: 38 pmol/s*mg protein) which was dose-dependently diminished to 60% of control by 400 mumol/l (+/-)-kavain. KCl depolarization (40 mmol/l) provoked an increase in [Ca2+]i and glutamate release almost identical to the responses elicited by 4-aminopyridine but 400 mumol/l (+/-)-kavain suppressed only the rate of glutamate release by 9% of control. The data suggest an interaction of (+/-)-kavain with voltage-dependent Na+ and Ca2+ channels, thereby suppressing the 4-aminopyridine-induced increase in [Na+]i, [Ca2+]i and the release of endogenous glutamate.

Coronary artery and saphenous vein graft remodeling: A review of histologic findings after various interventional procedures--Part III

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part III of this six-part series focuses on intimal proliferation and chronic recoil in patients undergoing previous remodeling techniques by balloon angioplasty.

Inhibition of neuronal activity in rat hippocampal slices by Aconitum alkaloids

The structurally related Aconitum alkaloids aconitine, lappaconitine, and 6-benzoylheteratisine inhibited the orthodromic and antidromic population spike in hippocampal CA1 area in a frequency-dependent manner. Aconitine (1 microM) completely suppressed epileptiform activity induced by omission of Mg2+ as well as normal neuronal activity, whereas lappaconitine (10 microM) and 6-benzoylheteratisine (10 microM) diminished epileptiform activity by sparing normal neuronal activity.

Structure and dynamics of oligosaccharides: NMR and modeling studies

Recent advances in the conformational analysis of oligosaccharides have focused on protein-bound oligosaccharides, glycopeptides, and glycoproteins, as well as on the conformational dynamics about glycosidic linkages. Significant progress has been made possible by dramatic improvements in NMR techniques and advances in computational chemistry and technology. Transferred nuclear Overhauser effects have been used to infer the conformations of carbohydrate ligands bound to protein receptors such as antibodies, lectins and enzymes. The increased use of combined NMR spectroscopic and computational protocols has resulted in insights into the dynamics of glycan chains.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part II

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part II of this six-part series focuses on morphologic causes of acute closure after remodeling and discusses findings late after successful balloon angioplasty remodeling.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part I

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part I of this six-part series focuses on mechanisms of remodeling after various interventional techniques, particularly balloon angioplasty.

Conformational analysis of blood group A trisaccharide in solution and in the binding site of Dolichos biflorus lectin using transient and transferred nuclear Overhauser enhancement (NOE) and rotating-frame NOE experiments

The present study is concerned with the elucidation of the conformation of the blood group A trisaccharide (alpha-D-GalNAc(1-3)[alpha-L-Fuc(1-->2)] beta-D-Gal-O-R) in the combining site of Dolichos biflorus seed lectin by use of 400-MHz and 600-MHz NMR spectroscopy. D. biflorus lectin displays a unique specificity for GalNAc residues. It occurs in solution as a tetrameric assembly having a molecular mass of 110 kDa, with two carbohydrate-binding sites per molecule. First, NOE build-up curves were obtained for the free blood group A trisaccharide from one-dimensional transient NOE experiments. Simulated NOE build-up curves were constructed from an ensemble of low-energy conformers derived from previous investigations. The comparison of theoretical and experimental data indicates that an equilibrium between two families of low-energy conformers most likely reflects the solution behavior of the trisaccharide in solution. Two-dimensional transferred NOE and rotating-frame enhancements (ROE) were subsequently measured for the trisaccharide complexed with the D. biflorus seed lectin. In addition to the NOEs observed for the free trisaccharide, the transferred NOESY spectrum showed several new NOEs that were identified as spin diffusion using a rotating-frame NOESY (ROESY) experiment. Experimental interglycosidic transferred nuclear Overhauser effect (TRNOE) build-up curves were compared to theoretical curves calculated for both low-energy conformers located in the D. biflorus lectin-binding site. Calculations of theoretical TRNOE were performed using a combination of the full relaxation matrix and the protein-ligand exchange matrix. Comparison between experimental and simulated TRNOE volumes leads to the conclusion that one conformation of blood group A trisaccharide is selected upon binding by D. biflorus lectin.

Nonatherosclerotic causes of coronary artery narrowing--Part III

Approximately 5% of patients with acute myocardial infarction do not have atherosclerotic coronary artery disease but have other causes for their luminal narrowing. The third part of this three-part review of nonatherosclerotic causes of coronary narrowing focuses on coronary vasculitis, infectious diseases, Kawasaki's disease, metabolic disorders, metastatic disease, and substance abuse (cocaine).

Continuous enzyme-linked fluorometric detection of L-(+)-lactate released from rat brain vesicles under anoxic conditions

A method is described for the on-line detection of L-(+)-lactate released from brain vesicles under physiological conditions. The principle of L-lactate detection is based on the reversible oxidation of L-lactate catalysed by L-lactate dehydrogenase (LDH, EC 1.1.1.27) employing 3-acetylpyridine-adenine-dinucleotide (APAD) as analogue of NAD according to the reaction: L-lactate + APAD reversible pyruvate + APADH. In practical terms, L-lactate synthesis of vesicles incubated in the presence of LDH and APAD was continuously followed by the fluorescence (490 nm) of APADH excited at 410 nm. Addition of a L-lactate standard (10 mumol/l) enhanced APADH fluorescence with a half-life of 6.0 +/- 0.6 s allowing us to uncover a short-term alteration of L-lactate synthesis. This method was applied to evaluate a prospective change of L-lactate generation caused by the anoxia-induced increase in intravesicular Na+ and Ca2+ concentration ([Na+]i, [Ca2+]i), both fluorometrically determined by SBFI and Fura, respectively. Upon anoxia, [Na+]i and [Ca2+]i increased continuously up to 40 mmol/l Na+ and 900 nmol/l Ca2+ within 400 s. Concurrently, intravesicular NADH ([NADH]i) and basal L-lactate synthesis were enhanced within a few seconds, the latter from 4.2 +/- 1.5 to 15.8 +/- 1.5 nmol L-lactate/min per mg protein. Incubation of vesicles in the presence of 10 mumol/l tetrodotoxin (TTX) suppressed the increase in [Na+]i and [Ca2+]i but failed to influence L-lactate synthesis. The data indicate a continuous Na+ influx via voltage-dependent Na+ channels accompanied by an increase in [Ca2+]i during anoxia which did not affect anaerobic L-lactate synthesis. The method of fluorometric L-lactate determination was confirmed to be suitable for the detection of L-lactate released under physiological conditions from brain vesicles and seems to be applicable to various cell models.

Nonatherosclerotic causes of coronary artery narrowing--Part II

Part II of this three-part article on nonatherosclerotic causes of coronary heart disease focuses on myocardial bridges, coronary artery aneurysms, emboli, coronary dissection, and spasm as causes of luminal narrowing.

Nonatherosclerotic causes of coronary artery narrowing--Part I

Approximately 5% of patients with acute myocardial infarction do not have atherosclerotic coronary artery disease but have other causes for their luminal narrowing. The first part of this three-part review of nonatherosclerotic causes of coronary narrowing focuses on congenital coronary artery anomalies, coronary fistula, and high take-off position of coronary ostia.

Frequency-dependent inhibition of neuronal activity by lappaconitine in normal and epileptic hippocampal slices

1. Extracellular recording of the stimulus-evoked population spike in the CA1 region of rat hippocampal slices in vitro was performed in order to investigate whether lappaconitine affects neuronal excitability. Lappaconitine is a diterpene alkaloid of plants of the Aconitum genus and has analgesic properties. 2. The results reveal an inhibitory action of lappaconitine (10 microM) manifested in a slow attenuation of the orthodromic and antidromic population spike. 3. The lappaconitine-induced inhibitory action was activity-dependent, that is, it was potentiated when frequency of electrical stimulation was increased. In contrast, washout of the neurotoxin was accelerated when stimulation frequency was decreased. 4. The activity-dependent action of lappaconitine raised the question of whether the drug is effective in suppressing the aberrant neuronal activity that occurs during an epileptic seizure. The results obtained from experiments on epileptic hippocampal slices demonstrated a selective reduction of the later spikes in the bursts with less effect on normal neuronal activity. 5. These data support the conclusion that lappaconitine, in addition to its antinociceptive effect, also has antiepileptic potency due to its highly activity-dependent mode of action.