Glucose homeostasis and the gastrointestinal tract: insights into the treatment of diabetes

The gastrointestinal tract is increasingly viewed as a critical organ in glucose metabolism because of its role in delivering glucose to the circulation and in secreting multiple glucoregulatory hormones that, in concert with insulin and glucagon, regulate glucose homeostasis. Under normal conditions, a complex interplay of these hormones acts to maintain plasma glucose within a narrow range despite large variations in the availability of glucose, particularly during transition from the fasting to fed state. In the fed state, the rate at which nutrients are passed from the stomach to the duodenum, termed gastric emptying rate, is a key determinant of postprandial glucose flux. In patients with diabetes, the regulation of glucose metabolism is disrupted resulting in fasting and postprandial hyperglycaemia. Elucidation of the role of the gastrointestinal tract, gut-derived glucoregulatory peptides and gastric emptying rate offers a new perspective on glucose homeostasis and the respective importance of these factors in the diabetes state. This review will highlight the importance of the gastrointestinal tract in playing a key role in glucose homeostasis, particularly in the postprandial period, and the role of established or new therapies that either leverage or modify gastrointestinal function to improve glycaemic state.

Factors associated with publication following presentation at a transplantation meeting

Full publication of abstracts presented at scientific meetings ranges from 25-74%. To determine the rate and factors associated with publication in organ transplantation, we examined abstracts presented at the American Transplant Congress in May 2000. Of 1147 abstracts, 607 (53%) achieved full publication at 4.5 years (mean 1.32 +/- 0.88 years). Fifty-nine percent (357/607) were published in three transplantation journals. For randomized trials, the proportion published was 61%. On multivariate analysis, industry sponsorship (OR 1.78; 95% CI 1.04-3.06), basic science research (OR 1.68; 95% CI 1.32-2.14), non-American center (OR 1.67; 95% CI 1.28-2.20) and oral presentation (OR 1.36; 95% CI 1.07-1.73) were independent predictors of full publication. Nearly half of all abstracts presented at a transplantation meeting remain unpublished. This finding needs to be considered when interpreting systematic reviews in the field of transplantation.

Oesophageal cancer and cachexia: the effect of short-term treatment with thalidomide on weight loss and lean body mass

BACKGROUND

Cachexia is common in patients with advanced cancer and has a direct impact on well-being and mortality.

AIM

To test the hypothesis that thalidomide can promote weight gain and lean body mass in patients with advanced oesophageal cancer.

METHODS

In an open-label study, 11 patients with non-obstructing and inoperable oesophageal cancer were established on an isocaloric diet for 2 weeks, followed by 2 weeks on thalidomide, 200 mg daily. The primary end-points were weight change and lean body mass. Secondary end-points were quality of life and changes in resting energy expenditure.

RESULTS

Ten patients completed the study protocol. The average caloric intake remained the same throughout the study period in all patients. Nine of 10 patients (95% confidence interval, 0.60, 0.98) lost weight on diet alone. The mean weight gain on thalidomide in the following 2 weeks was 1.29 kg (median, 1.25 kg). A similar trend was shown in the lean body mass. Eight of nine patients (95% confidence interval, 0.57, 0.98) initially lost lean body mass on diet alone (missing data in one patient). The mean gain in lean body mass on thalidomide in the following 2 weeks was 1.75 kg (median, 1.33 kg).

CONCLUSIONS

Thalidomide treatment appeared to reverse the loss of weight and lean body mass over the 2-week trial period.

An analysis of consultations with the crowd doctors at Glasgow Celtic football club, season 1999-2000

OBJECTIVE

To analyse all clinical presentations to the crowd doctors at Scotland's largest football stadium over the course of one complete season.

METHODS

A standard clinical record form was used to document all consultations with the crowd doctors including treatment and subsequent referrals. The relevance of alcohol consumption was assessed.

RESULTS

A total of 127 casualties were seen at 26 matches, a mean of 4.88 per match. Twenty casualties were transferred to hospital, including one successfully defibrillated after a cardiac arrest. Alcohol excess was a major contributing factor in 26 cases.

CONCLUSIONS

The workload of the crowd doctors was very variable and diverse. The social problem of excessive alcohol consumption contributed considerably to the workload. The provision of medical facilities at football grounds means that attendance there is now one of the least adverse circumstances in which to have a cardiac arrest. The study confirmed previous impressions that more casualties are seen at high profile matches.

Time of day effects in, and the relationship between, sleep quality and movement

The study aimed to measure the effects of a 27-h 'day' sleep-wake regime on actigraphic and subjective sleep variables, and to examine the relationships between these variables. Nine subjects spent 30 days and nights in the laboratory. After sleeping 8 h for each of 8 nights, the subjects had an imposed 27-h 'day', for 18 'days', remaining in bed for 9 h on each sleep period. Sleep periods therefore started 3 h later each day, although subjects' circadian rhythms stayed entrained to 24 h, because subjects were not isolated from the natural light-dark cycle. Time asleep, subjective sleep efficiency and subjective sleep quality, but not movement during sleep, were found to be significantly affected by time of going to bed. There were significant decreases in movement during recovery sleeps following each of two episodes of 26 h sleep deprivation. Over the study there were significant within-subject correlations between subjective sleep quality and subjective sleep efficiency (rav = 0.65), movement during sleep and subjective sleep efficiency (rav = -0.48), and movement during sleep and subjective sleep quality (rav = -0.26). We conclude that sleep movement, despite its low within- and between-subjects variability, is nevertheless a statistically reliable, but weak, indicator of subjective sleep efficiency and quality.

The difference between activity when in bed and out of bed. II. Subjects on 27-hour "days"

Nine healthy subjects have been studied while exposed to the normal alternation of light and dark, but with their sleep and activity pattern adjusted to a 27-h "day" for 17 imposed "days." Rectal temperature showed clearly the competing influences of 27-h and 24-h components, and these were separated by the method of "purification." The method indicated that the endogenous component had a constant amplitude throughout the experiment and remained entrained to solar (24-h) time; by contrast, the exogenous component followed the imposed 27-h "day" and increased rectal temperature in proportion to the amount of subjects' activity. Wrist movement was used to assess activity while in bed (attempting sleep) and out of bed (when naps were forbidden). While these results confirmed adherence of the subjects to the imposed 27-h "days," they also showed that the dichotomy between "out of bed" activity and "in bed" inactivity depended on the phase relationship between endogenous (24h) and exogenous (27h) components. Thus, the dichotomy was highest and was equal to that during control days (with a conventional 24-h life-style) when the two components were in phase and lowest when the solar and imposed day were in antiphase. This was due to changes in activity, both during time spent in bed and out of bed. We confirm that this protocol can produce valuable information about the properties of the circadian system in humans and the value of the process of purification of temperature data. We have established also that the very simple and noninvasive measurement of wrist movement, coupled with its use to calculate dichotomy indices, provides valuable information that both confirms and extends the results obtained from the more conventional (but also more invasive) measurement of rectal temperature.

Transforming growth factor-beta 1 cooperates with anti-immunoglobulin for the induction of apoptosis in group I (biopsy-like) Burkitt lymphoma cell lines

Group I Burkitt lymphoma (BL) cell lines, which retain the original biopsy phenotype, have been shown to enter apoptosis in response to a number of external stimuli including serum deprivation, thermal shock, addition of calcium ionophore, and ligation of surface immunoglobulin (Ig) by antibody. Transforming growth factor-beta 1 (TGF beta 1) is known to cause growth arrest in BL lines. Here we show that while it is by itself capable of promoting some degree of apoptosis in group IBL cells, TGF beta 1 cooperates with anti-immunoglobulin to this end. Trimeric soluble recombinant human CD40 ligand (sCD40L) was able to inhibit apoptosis induced by the combination of agonists to some degree, but such rescue proved to be short-lived. Both TGF beta 1 and anti-Ig individually caused BL cells to undergo growth arrest at the G1 phase of cell cycle before their entry into apoptosis: the consequence of sCD40L addition was to maintain the cells in cycle for longer. No induction of the apoptosis-protecting gene, bcl-2, occurred in the presence of sCD40L. These findings are discussed, particularly highlighting the relationship existing between survival and the cell cycle. The strong cooperative effects observed between anti-Ig and TGF beta 1 in promoting apoptosis and the inability of CD40 to signal for long-term rescue raise the potential for a novel therapeutic attack on B-cell lymphoma.

Engagement of CD20 suppresses apoptosis in germinal center B cells

In a screen of 67 monoclonal antibodies (mAb) included in the Blind Panel of B cell antibodies for the 5th International Workshop on Human Leukocyte Differentiation Antigens, only the CD20 mAb--included as a positive control for immunophenotyping studies--was found to suppress the spontaneous apoptosis which occurs in human germinal center (GC) B cells when placed in tissue culture at 37 degrees C. Further detailed study using the 1F5 mAb confirmed this observation, showing that rescue from apoptosis via CD20, while not as efficient as that obtained on ligating CD40, was of similar magnitude to that achieved on engagement of surface immunoglobulin (sIg) by immobilized antibody. Also similar to anti-Ig, the CD20 mAb rescued from apoptosis without priming for the proliferation of GC B cells: this was quite different to its action on resting, non-GC B cells, where it provides a potent priming signal for cell cycle progression in response to IL-4 or anti-CD40. Unlike the survival signal engendered via sIg, CD20 engagement neither mobilized Ca2+ from intracellular stores or opening of a Ca2+ channel with 1F5, nor did it affect the ability of anti-Ig to open a Ca2+ gate in GC B cells. An unexpected feature of CD20-mediated rescue of GC B cells from apoptosis was a failure to turn on Bcl-2 expression.

Insulin sensitivity in post-obese women

1. Both increased and decreased sensitivity to insulin has been proposed to precede the development of obesity. Therefore, insulin sensitivity was measured during a 2 h hyperinsulinaemia (100 m-units min-1 m-2) euglycaemic (4.5 mmol/l) glucose clamp combined with indirect calorimetry in nine weight-stable post-obese women and in nine matched control women preceded by 12 h fasting after 48 h on a standardized diet. 2. Both glucose disposal rate (post-obese women, 9.5 +/- 2.2 mg min-1 kg-1, control women, 11.2 +/- 1.4 mg min-1 kg-1, not significant) and glucose oxidation (3.6 +/- 0.5 mg min-1 kg-1 versus 4.0 +/- 0.7 mg min-1 kg-1, not significant) were similar in the two groups during the last 30 min of the clamp. Lipid oxidation also decreased similarly during the clamp in the post-obese women (from 30.4 +/- 12 to 2.0 +/- 7 J min-1 kg-1) and in the control women (from 33.6 +/- 11 to 5.4 +/- 8 J min-1 kg-1, not significant). Basal plasma concentrations of free fatty acids were similar, but at the end of the clamp free fatty acids were lower in the post-obese women than in the control women (139 +/- 19 and 276 +/- 48 mumol/l, P = 0.02). 3. We conclude that the insulin sensitivity of glucose metabolism is unaltered in the post-obese state. The study, however, points to an increased antilipolytic insulin action in post-obese subjects, which may favour fat storage and lower lipid oxidation rate postprandially.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of human B lymphocytes by phorbol esters reported to be selective in the protein kinase C isoforms they activate

It is reported here that B cells can be stimulated by two phorbol esters which, in cell free substrate phosphorylation assays, are selective in the PKC isoforms they activate: thymeleatoxin (Thy) stimulates all of the classical (c) or Group A PKCs (alpha, beta 1, beta 2 and gamma) but not PKC delta and epsilon which belong to the novel (n) or Group B PKCs, while 12-deoxyphorbol-13-O-phenylacetate-20-acetate (dPPA) is a specific activator of PKC beta 1. By itself, phorbol 12-myristate, 13-acetate (PMA)--which activates all cPKC and nPKC--was, on a molar basis, some 40-times more potent than either Thy or dPPA which were themselves equipotent at promoting DNA synthesis in resting B cells: the peak response achieved with Thy and dPPA was higher (1.4 x) than that obtained with PMA. In the presence of calcium ionophore, PMA, Thy and dPPA all stimulated a higher (and equivalent) peak response which was achieved at a lower phorbol ester concentration in each case: however, whereas Thy now approached PMA in potency, dPPA remained some 40-times less potent.

Decrease in the size of the myotonic dystrophy CTG repeat during transmission from parent to child: implications for genetic counselling and genetic anticipation

Recently an unstable trinucleotide CTG repeat, located within the 3' untranslated region of a gene on 19q13.3 was discovered in kindreds with myotonic dystrophy (DM). The age-of-onset/severity of DM shows a good correlation with CTG repeat size, and pedigrees and data reported to date have shown a striking trend toward amplification of the size of the CTG repeat during transmission from parent to child. The amplification has been accepted as the biological explanation for anticipation in the clinical severity observed in many families with DM. In this paper we report on 3 families where CTG amplification decreased during transmission from parent to child. In one case there was a gene conversion event, while in the remaining 2 there was a simpler reduction in the size of the repeat length. The changes appear to have been accompanied by a reduction in clinical severity in the child when compared to the parent. These observations are discussed in terms of their clinical implications and the biases that may exist in much of the reported data.

Leber's hereditary optic neuropathy: a model for mitochondrial neurodegenerative diseases

A number of human diseases have been attributed to defects in oxidative phosphorylation (OXPHOS) resulting from mutations in the mitochondrial DNA (mtDNA). One such disease is Leber's hereditary optic neuropathy (LHON), a neurodegenerative disease of young adults that results in blindness due to atrophy of the optic nerve. The etiology of LHON is genetically heterogeneous and in some cases multifactorial. Eleven mtDNA mutations have been associated with LHON, all of which are missense mutations in the subunit genes for the subunits of the electron transport chain complexes I, III, and IV. Molecular, biochemical, and population genetic studies have categorized these mutations as high risk (class I), low risk (class II), or intermediate risk (class I/II). Class I mutations appear to be primary genetic causes of LHON, while class II mutations are frequently found associated with class I genotypes and may serve as exacerbating genetic factors. Different LHON pedigrees can harbor different combinations of class I, II, or I/II mtDNA mutations, as shown by the complete sequence analysis of the mtDNAs of four LHON probands. The various mtDNA genotypes included an isolated class I mutation, combined class I+II mutations, and combined class I/II+II mutations. The occurrence of such genotypes supports the hypothesis that LHON may result from the additive effects of various genetic and environmental insults to OXPHOS, each of which increases the probability of blindness.

Apparent Smith-Lemli-Opitz syndrome in a child with a previously undescribed form of mucolipidosis not involving the neurons

A diagnosis of Smith-Lemli-Opitz syndrome was made shortly after birth in a small-for-dates infant, on the basis of a characteristic face, penoscrotal hypospadias, bilateral postaxial hexadactyly, and bilateral syndactyly of toes 2-3. The clinical course was marked by failure to thrive, severe delay, refractory myoclonic jerks beginning at age 2 months, and increasing hepatosplenomegaly. He developed corneal clouding and increased gingival hypertrophy and died at age 18 weeks. Autopsy disclosed widespread storage of mucopolysaccharides and lipids within the macrophages and, to a lesser extent, parenchymal cells, of all organ systems. There was extensive demyelination of the cerebral white matter, and dystrophic calcification in the cerebrum, cerebellum, and brainstem. There was no evidence of primary neuronal involvement in the storage. Although the chance concurrence of 2 uncommon diseases is rare, a causal link between the clinical anomalies and the storage disorder cannot be argued convincingly on the basis of one case. Careful pathologic studies of other children who die with clinical signs compatible with Smith-Lemli-Opitz syndrome are indicated.

Use of the polymerase chain reaction for the differential cross screening of libraries cloned into phage-lambda-based vectors

We describe a simple and rapid method that can be used to identify sequences present in any two DNA libraries (either genomic or cDNA), provided only that the libraries are in different vectors with different cloning sites. This procedure makes use of the polymerase chain reaction (PCR) to amplify the inserts of one library. The product of the PCR reaction is then used to screen a second library to identify sequences which are common to both. We illustrate the use of this method for the systematic isolation of human X-chromosome-linked genomic clones that harbor sequences expressed in human chorioretinal tissue.

Management of achalasia and laryngo-tracheal compression

A case of severe airway obstruction due to laryngo-tracheal compression associated with achalasia is presented. Local anaesthetic tracheostomy has an important role in some cases.

Mycobacterium chelonei keratitis in a soft-contact-lens wearer

A 29-year-old woman who had successfully used extended-wear soft contact lens for 7 years was found to have a corneal ulcer due to Mycobacterium chelonei. Unique to this presentation was the lack of a history of severe corneal trauma, prior surgery or immunocompromised tissue. Despite in-vitro resistance of the organism to amikacin sulfate, topical therapy with this antibiotic led to a complete cure without the need for surgical intervention.

Infectious crystalline keratopathy

Crystalline deposits developed in the anterior third of the stroma in a 60-year-old woman. The deposits resolved only after aggressive treatment with intravenously given penicillin and topical erythromycin and vancomycin hydrochloride. Review of reported cases indicated that infectious crystalline keratopathy is caused by chronic colonization of the stroma by bacteria, usually streptococci of the viridans group. Local tissue trauma, concomitant use of topical corticosteroids, an intact overlying epithelium and use of a bandage-type soft contact lens are factors in the development of the infection. Patients with crystalline formations in this setting should undergo early lamellar biopsy for histologic examination, culture and sensitivity testing, followed by aggressive therapy with appropriate antibiotics.

In situ detection of rubella RNA and antigens in cultured cells

We developed in situ hybridization and immunofluorescent procedures to detect rubella RNA and antigens in tissue-cultured cells infected with rubella virus. cDNA fragments of the rubella virus E1 structural gene were used as probes for in situ hybridization to detect rubella RNA sequences in Vero cells infected with rubella virus. Using antibodies against rubella proteins, indirect immunofluorescence detected rubella virus structural proteins in Vero cells infected with rubella virus. The immunofluorescence method has also been applied to study the expression of rubella polypeptide E1 in transfected COS cells and may be applied to the detection and study of persistent rubella virus infection in human tissues.

Recurrent and residual renal calculi in children

One hundred and thirteen children with non-metabolic urinary tract calculi were operated on between 1960 and 1983. One hundred were followed up for 3 to 17 years (mean 8.2). Seventeen children (15%) developed recurrent calculi after complete clearance at the initial operation and in 13 of these the stones recurred within 5 years. Proteus urinary infection was a constant feature of stone recurrence. Five patients required re-operation for removal of the recurrent calculus. Small residual caliceal fragments were left behind in 17 children but only 3 required surgical removal.

Neuroaxonal dystrophy presenting with neonatal dysmorphic features, early onset of peripheral gangrene, and a rapidly lethal course

Infantile neuroaxonal dystrophy (IND) is a well-established autosomal recessive neurodegenerative disease. Clinical signs generally begin toward the end of the first or during the second year of life. We are aware of at least 4 cases of pre- or perinatal onset of this condition, and report here on 2 brothers who were affected at birth and had an unusual clinical course with onset of peripheral gangrene that progressed to autoamputation of digits. Both boys died in infancy with pathological changes compatible with IND. The somewhat different clinical course in these brothers leaves open the possibility that this is a variant of neuroaxonal dystrophy due to an X-linked recessive mutation.

A microcomputer-based data acquisition system for a prosthetic heart valve test apparatus

The hydrodynamic testing of prosthetic heart valves in the laboratory under pulsatile flow conditions remains the only way of obtaining detailed information about valve function. Test procedures have become increasingly sophisticated, with a variety of different test conditions and detailed analysis of the pressure and flow signals. A computerized data acquisition system has been developed for use with the Glasgow pulsatile flow test apparatus. The computer collects seven signals from the test rig over a period of 20 s, and calculates the average waveform for each signal. Standard parameters, such as mean pressure differences, mean flows, regurgitant volumes and energy losses, are calculated automatically. The complexity of the analysis and the need for standardized documentation makes computerization essential. The system has been used extensively for function tests on over 160 prosthetic heart valves.

A system for solar radiation data storage and analysis

It is important for photodermatologists to have an accurate and continuous measurement of the ultraviolet radiation reaching the ground. This implies the establishment of a network of detectors, but for this to be a practical reality, it is essential that an accurate and convenient system be adopted for data storage and analysis. To this end we have developed a system which meets the following criteria: it is automatic; component costs are low: it uses a home microcomputer costing 400 pounds (less than $600); because processing is done by a computer, it is flexible; also, for the same reason, there is the facility for on-line display and on-line analysis; there are no significant errors: a modified computer circuit produces a temperature coefficient of 30 ppm/degrees C; reliability is good: 12 d of data were lost from all causes, including development, during 12 months of continuous use. The system described could form the basis of a practical UV-recording network.

Detection of antibodies to individual proteins of rubella virus

Individual rubella virus structural polypeptides were electroeluted from SDS-polyacrylamide gels. The eluted polypeptides were used, without further purification, as antigens in ELISA assays for the detection of rubella-specific antibodies in patients' sera. This provided a more sensitive detection method than that involving classical serological assays such as HI or VN or that using immunoprecipitation. Antisera against individual viral polypeptides were raised in mice. No haemagglutination inhibition activity was observed in any of these sera and weak virus neutralizing activity was only detected with antiserum to the E1 protein. Antisera to either the E1 or E2(a,b) complex proteins cross-reacted with both the E1 and E2(a,b) complex proteins.

Expression of the mammalian c-fes protein in hematopoietic cells and identification of a distinct fes-related protein

The avian c-fps and mammalian c-fes proto-oncogenes are cognate cellular sequences. Antiserum raised against the P140gag-fps transforming protein of Fujinami avian sarcoma virus specifically recognized a 92,000-Mr protein in human and mouse hematopoietic cells which was closely related in structure to Snyder-Theilen feline sarcoma virus P87gag-fes. This polypeptide was apparently the product of the human c-fes gene and was therefore designated p92c-fes. Human p92c-fes was associated with a tyrosine-specific protein kinase activity in vitro and was capable of both autophosphorylation and phosphorylation of enolase as an exogenous protein substrate. The synthesis of human and mouse p92c-fes was largely, though not entirely, confined to myeloid cells. p92c-fes was expressed to relatively high levels in a multipotential murine myeloid cell line, in more mature human and mouse granulocyte-macrophage progenitors, and in differentiated macrophage like cells as well as in the mononuclear fraction of normal and leukemic human peripheral blood. p92c-fes was not found in erythroid cells, with the exception of a human erythroleukemia line which retains the capacity to differentiate into macrophage like cells. These results suggest a normal role for the p92c-fes tyrosine kinase in hematopoiesis, particularly in granulocyte-macrophage differentiation. In addition, a distinct 94,000-Mr polypeptide, antigenically related to p92c-fes, was identified in a number of hematopoietic and nonhematopoietic human and mouse cells and was also found to be associated with a tyrosine-specific protein kinase activity.

Comparison of personal pollution monitoring techniques for use in the operating room

Three personal pollution monitors (adsorption tubes, diffusion dosimeters and evacuated bottles) have been tested, in routinely used operating rooms and under controlled laboratory conditions, for their accuracy and reproducibility relative to one another and to measurements by infra-red spectroscopy. All the techniques provide time-weighted average measurements of pollutant concentrations. Tubes and dosimeters measure halothane with greater accuracy than that required by N.I.O.S.H. regulations, but neither technique can measure inorganic pollutants such as nitrous oxide. The prototype evacuated bottles tested are unsatisfactory at their present stage of development for the measurement of both halothane and nitrous oxide concentrations. We believe that, at the present time, surveys of operating room pollution can best be carried out using adsorption tubes of diffusion dosimeters for personal halothane concentrations and a portable infra-red spectrometer for measurement of background nitrous oxide concentrations.

Survey of operating room pollution within an N.H.S. district

Pollution by waste anaesthetic gases was measured in all operating departments in a typical N.H.S. district. Methods were chosen to provide time-weighted average levels over the period of each operating session. The results showed that air-conditioning alone could not guarantee pollution levels below suggested maximum levels and that to meet those requirements air-conditioning plus scavenging was necessary. Background pollution levels were found to be representative of the personal exposure of nursing staff but approximated to only one third of the anaesthetists' personal exposure. Dental clinics presented special problems, namely the very high levels of pollution to which the dentist and his assistants were exposed.

Effect of glycerol on triglyceride metabolism in the rat

Lipid metabolic studies were carried out on the male Wistar rats fed on glycerol-rich diet in order to elucidate the mechanism of glycerol-induced hypertriglyceridemia. No difference was found between the glycerol fed rats and the control rats in the rate of triglyceride secretion from the liver measured by the Triton WR-1339 method as well as in the rate of incorporation of labeled glycerol into liver triglyceride. The facts that the half-life of the intravenously injected Intralipid in the blood was significantly delayed in the glycerol fed rats and that the lipoprotein lipase activity released from epididymal adipose tissue of the glycerol fed rats was markedly decreased to 19% of that of the control rats seem to account for the serum triglyceride elevation induced by the glycerol feeding.

Gas chromatographic determination of Ostwald solubility coefficients for cyclopropane, halothane and trichloroethene (trichloroethylene)

Gas chromatographic methods using solvent extraction for the analysis of cyclopropane and and trichloroethene (trichloroethylene) are described and evaluated; cyclopropane was extracted into carbon tetrachloride and trichloroethene into carbon disulphide, using chloroform and toluene respectively as the internal standards. Ostwald solubility coefficients were measured for cyclopropane, halothane and trichloroethene in Krebs solution: at 310 K the respective values +/- SEM of the Ostwald coefficients are 0.181 +/- 0.009, 0.78 +/- 0.02 and 1.54 +/- 0.02; over the temperature range 295-310 K the respective temperature coefficients of solubility are -2.27, -4.18 and -3.81 in units of per cent/K at 310 K.

Prazosin and hydrallazine in the treatment of hypertension

1. Two vasodilators, prazosin and hydrallazine, have been compared in three double-blind cross-over studies designed to test their effect when used in combination with a beta-adrenoceptor-blocking agent and a thiazide. 2. Single doses of 3 mg of prazosin or 75 mg of hydrallazine were administered to patients whose blood pressures remained uncontrolled on a thiazide and a beta-adrenoceptor-blocking agent. Both agents produced significant falls in systolic and diastolic blood pressure apparent at 1 h. The effects of prazosin persisted for 6-7 h and those of hydrallazine for 4-6 h. Tachycardia was more marked and more prolonged after hydrallazine and continued after the blood pressure had risen to base-line levels or above. 3. In 6 week and 12 week double-blind cross-over studies, mean falls in blood pressure were similar with prazosin and hydrallazine. Similar falls in the supine diastolic blood pressure were achieved with 1 mg of prazosin and 20 mg of hyrallazine, but for a given fall in supine diastolic blood pressure, prazosin produced a significantly lower standing diastolic blood pressure. 4. Severe side effects were more pronounced after hydrallazine, which necessitated withdrawal of seven patients, whereas only one patient on prazosin withdrew from the trial because of side effects.

Halothane 0.2-4% analysis by gas chromatography

The katharometer detector is better suited to the analysis of gaseous halothane (0.2-4%) than is the flame ionization detector, since the peak heights are directly proportional to concentration, and are more reproducible.