Long-term nutrient enrichment of an estuarine system: Ythan, Scotland (1958-1993)

A comprehensive review is given of past and current annually averaged nutrient concentrations (total oxidised nitrogen [TON], phosphate and silicate) in the River Ythan and its estuary. TON concentrations in the River Ythan have increased from ca 100-150 microm in the late 1960s to ca 500-550 microm in the early 1990s, changes which are also shown in the estuary. The interpretation of the phosphate data is more complex but concentrations in the estuary also appear to have increased. Silicate concentrations have remained constant with time. The results of 11 surveys of the estuary completed during 1993 are given. TON and silicate behave conservatively in the estuary, with concentrations determined by those of the fresh water end-member and hence by processes within the catchment. Phosphate and ammonia concentrations at low salinity are affected by the discharge from the Ellon sewage treatment facility at the head of the estuary. Throughout the estuary there is evidence of an input of ammonia to the water column from the sediments, but it represents only ca 0.2-2% of the nitrogen entering from the River Ythan. Despite the increased nutrient loading to the estuary there is no evidence that this has resulted in higher chlorophyll concentrations in the water column, this observation is attributed to the relatively short flushing period of the estuary.

Characterization of a small supernumerary ring X chromosome by fluorescence in situ hybridization

We report on a male with mild learning disabilities who has a supernumerary marker chromosome. The marker chromosome was defined by fluorescence in situ hybridization as a ring X chromosome with breakpoints in the juxacentromeric region. Replication studies suggest that the ring X is late-replicating. However XIST, a gene in the X inactivation centre interval which is expressed exclusively from the inactive X chromosome, is not present on the marker, nor is it expressed in the patient's cells. These results are discussed with respect to karyotype-phenotype correlations and X inactivation.

Randomized placebo-controlled trials of antibiotics for acute bronchitis: a critical review of the literature

BACKGROUND

Acute bronchitis is a common clinical problem that causes considerable morbidity and presents both diagnostic and treatment dilemmas for the physician. An evaluation of all published randomized controlled trials of antibiotics in the treatment of acute bronchitis was conducted to (1) quantitatively assess methodologic rigor, (2) determine if effectiveness of antimicrobial therapy is known, and (3) analyze strengths and weaknesses of randomized controlled trials in family practice settings.

METHODS

A scoring system for the evaluation of randomized controlled trials was adapted for this study. Four raters, who were blinded to which journals published the studies and the type of antibiotic used in each study, assessed the six-randomized clinical trials for treatment of bronchitis identified through a literature search. The trials were rated according to criteria that measured internal validity.

RESULTS

Scores for internal validity ranged from 65.5 to 102.5 points with a maximum possible score of 120 points (54.6% to 85.4%). The two trials with the highest scores assessed doxycycline and showed no benefit from use of this antibiotic. Single trials that studied erythromycin and trimethoprim-sulfamethoxazole showed improvement in outcome from use of these drugs; however, of the six trials, these two studies ranked fourth and fifth for internal validity. Low scores resulted from small sample size, possible contamination with other treatment measures, and poor assessment of subjects' compliance with antibiotic regimen.

CONCLUSIONS

An evaluation of the current literature does not support antibiotic treatment for acute bronchitis. Further studies of this common illness are indicated. It is hoped that this critical review of randomized control trials will prove useful in the planning of future studies, in placing greater emphasis on methodologic rigor, and in giving greater consideration to the practical constraints of research in the family practice setting.

An evaluation of the multidisciplinary approach to psychiatric diagnosis in elderly people

OBJECTIVE

To determine the accuracy of psychiatric diagnoses made by two community psychogeriatric teams operating a multidisciplinary assessment procedure.

DESIGN

Comparison of team diagnosis with independent formal assessment and consensus diagnosis by research psychiatrists.

SETTING

Two community psychogeriatric teams with similar operational policies in an inner London health district.

SUBJECTS

100 people aged 65-90 (70 women) newly referred to the teams.

MAIN OUTCOME MEASURES

Concordance between team and research diagnoses.

RESULTS

Agreement between team and research diagnoses ranged from 90% to 99% for the specific psychiatric disorders studied. There was no significant difference between medical and non-medical team members in their diagnostic performance compared with the research psychiatrists. Increased diagnostic accuracy by team members was associated with longer experience of team working, regardless of the team members' professional background.

CONCLUSIONS

The multidisciplinary approach to the assessment of referrals to these community teams for the elderly is not associated with misdiagnosis of psychiatric disorder.

Relaxant effects of alpha-adrenoceptor agonists in the rat isolated gastric fundus

In rat gastric fundus preparations with tone raised by the addition of barium chloride or carbachol, and in the presence of propranolol (2 microM) to prevent beta-adrenoceptor mediated effects, the adrenoceptor agonists noradrenaline, adrenaline, alpha-methylnoradrenaline, isoprenaline, cirazoline and phenylephrine all caused concentration-related relaxant responses. Relaxations to the catecholamines were poorly antagonized by prazosin (0.01-1 microM) resulting in the slopes of Schild plots being less than unity, low pA2 values for prazosin against the catecholamines and a clear relaxant effect of the catecholamines even in the presence of 1 microM prazosin. The prazosin-resistant relaxations were unaffected by higher concentrations of prazosin (2 microM) and propranolol (30 microM) or by further additions of idazoxan (1 microM) or haloperidol (30 microM). The relaxations were not due to a non-specific effect of the catechol nucleus since neither dihydroxyphenylethylene glycol (DOPEG) nor dihydroxyphenylacetic acid (DOPAC) produced relaxant effects at concentrations up to 300 microM. In contrast to the results with the catecholamines, prazosin was a potent antagonist of the relaxant effect of cirazoline and phenylephrine, although the antagonism was difficult to quantify due to a lowering of the slope of the concentration response curves to cirazoline and phenylephrine with the higher concentrations of prazosin (0.1 and 1.0 microM). In conclusion postjunctional relaxatory effects of catecholamines in the rat gastric fundus are mediated partly via alpha 1-adrenoceptors and partly via an atypical adrenoceptor.

Controlled trial of heater probe treatment in bleeding peptic ulcers

A prospective randomized controlled trial of endoscopic heater probe therapy in bleeding peptic ulcers was performed to determine whether probe therapy can reduce rebleeding rates. Of 630 patients endoscoped for suspected upper gastrointestinal haemorrhage over a 16-month period, 166 (26 per cent) were found to have a peptic ulcer. Either minor or no stigmata of recent haemorrhage were found in 115 patients at the time of endoscopy. A single peptic ulcer with either active haemorrhage or a visible vessel was found in 51 patients, 43 of whom were entered into the trial. There were eight exclusions: four were inaccessible, one was a torrential haemorrhage and three were excluded for non-technical reasons. Patients were randomized to receive either heater probe (n = 20) or sham (n = 23) therapy. In actively bleeding ulcers, immediate haemostasis was achieved following probe therapy in 14 of 18 patients (78 per cent) compared with none of 21 having sham treatment (P less than 0.002). No rebleeding occurred in the probe therapy group (n = 20) compared with rebleeding in five of 23 sham treated patients (P = 0.05). Urgent surgery for haemostasis was required in three of the five sham treated patients who rebled. It is concluded that heater probe therapy may be effective in reducing rebleeding rates in peptic ulcers accessible to the endoscope.

Rebound nocturnal hypersecretion after four weeks treatment with an H2 receptor antagonist

Daytime intragastric pH, fasting and meal stimulated serum gastrin and nocturnal acid output were studied in eight male duodenal ulcer patients before, during and two days after completing nizatidine 300 mg nocte (20:00 h) for four weeks. Median nocturnal acid output (mmol/10 h) decreased during treatment to 11.6 (range 0.4-26.7) compared with pretreatment value of 39.4 (9.8-91.2); median acid inhibition 77% (p less than 0.01) which was strongest between 24:00 and 04:00 h. Two days after discontinuing treatment, nocturnal acid output increased to 74.1 (11-181). Compared with the pretreatment value this represents median rebound hypersecretion of 77% (p less than 0.05), caused by increased H+ concentration and volume of secretion. Overall median daytime intragastric pH (09:00-21:00 h) was unchanged on the final day of treatment and two days after completing therapy, compared with the pretreatment values. Fasting serum gastrin measured between 09:30 and 10:00 h and the integrated gastrin response to an OXO breakfast taken out at 10:00 h were also similar during and after treatment, compared with pretreatment values. The rebound nocturnal hypersecretion may be relevant to the high ulcer relapse rates after stopping H2 receptor antagonists.

Twin birth and adult psychiatric disorder. An examination of the case records of the Maudsley Hospital

We compared the general distribution of diagnoses in 20,895 patients at the Maudsley Hospital with that of 504 patients born twins, including 117 twins where the co-twin had died before the age of 15. Significant differences in diagnostic distribution were found in the co-twin-dead compared with the co-twin-alive group; the former received diagnoses of schizophrenia, personality disorder, or substance abuse more often than the latter. While there were no overall differences between twins and non-twins, there were relatively more twins in the above three diagnostic groups. We suggest that the factors leading to the death of one twin are implicated in the later psychiatric morbidity of the survivor.

The practical problems of nutritional support for children on continuous ambulatory peritoneal dialysis

Data are presented from the results of 46 dietary assessments on 13 children on continuous ambulatory peritoneal dialysis (CAPD). The results demonstrate that even with dietary supplements, energy and protein intakes are generally inadequate. Nutritional requirements and possible reasons for suboptimal intake are discussed and potential methods for improving nutritional intake are suggested.

Distribution of sodium valproate in normal whole blood and in blood from patients with renal or hepatic disease

Sodium valproate at a concentration of 300 mumol/l in whole blood, partitioned between the red blood cell and plasma to produce a red blood cell/plasma partition ratio of 0.20. Red blood cell uptake was proportional to percent free drug in plasma and uptake was maximal when plasma was replaced by buffer, producing a red blood cell/buffer ratio of 0.87. Reduction of plasma protein binding by plasma dilution, by increasing the total sodium valproate plasma concentration, or by renal or hepatic disease in 24 patients, caused a predictable rise in red blood cell uptake of drug. The red blood cell represented a relatively small compartment for free sodium valproate in blood, however uptake of the drug into this compartment increased considerably in states of reduced plasma protein binding. Because the concentration of drug in the red blood cell reflects free drug concentration in plasma, the red blood cell may serve as an indicator of free drug changes in blood.

Intracranial tuberous sclerosis in infancy

Transfontanelle sonograms and CT scans of the brain were obtained in 2 infants with tuberous sclerosis. Each modality showed typical subependymal nodules in both infants, as well as a large mass adjacent to the foramen of Monro in one of them; in the other, peripheral cortical tubers were clearly outlined with CT but not detected by ultrasound.

Antibodies to liver-specific lipoprotein in children with chronic liver disease due to "autoimmune" chronic active hepatitis, cystic fibrosis, and alpha 1-antitrypsin deficiency

Antibodies to a liver-specific lipoprotein complex (LSP) were determined by radioimmunoassay in the sera of 65 children with possible chronic liver disease. Thirteen had "autoimmune" chronic active hepatitis (CAH), 21 alpha 1-antitrypsin deficiency PiZ (alpha 1-ATD), all having significant liver disease, while 10 of 31 children with cystic fibrosis (CF) had abnormal biochemical tests of liver function, six having cirrhosis. Sera from 12 (92%) of 13 untreated CAH patients contained detectable anti-LSP antibodies, the highest titres occurring in those with anti-liver/kidney microsomal or smooth muscle antibodies. Titre of anti-LSP antibodies correlated with piecemeal necrosis of periportal hepatocytes in liver biopsies, but not with standard biochemical tests of liver function or serum immunoglobulin concentrations. The incidence of LSP antibodies fell as liver damage improved with immunosuppressant therapy, being positive in 18 of 26 sera from children in whom the transaminases were still above normal, but positive in only two of 20 in whom transaminase values were within the normal range (chi 2 = 16, p less than 0.001). Sera from two of 31 patients (6%) with CF contained anti-LSP antibodies as did sera from six of 21 patients with alpha 1-ATD. Antibody concentrations were lower than in CAH, and in alpha 1-ATD the presence of anti-LSP could not be correlated with the presence or absence of piecemeal necrosis on liver biopsy. Our data suggest that autoimmune mechanisms involving antibody to hepatocyte membrane components have a role in the pathogenesis of chronic liver disease in autoimmune CAH in children as in adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Immune responses in patients with obstructive jaundice of infancy. Anti-LSP and Clq binding in sera

To investigate possible involvement of immune responses in the pathogenesis of obstructive jaundice in infancy we measured antibody to liver specific lipoprotein (LSP) by radio immunoassay and immune complexes by their ability to bind C1q in sera from 16 patients with extrahepatic biliary atresia and 16 with neonatal hepatitis and 13 age matched controls. Anti-LSP was present in 6 of 16 with preoperative biliary atresia and 6 of 16 with hepatitis. Mean percentage C1q bound was higher in hepatitis (22 SD 15%) than preoperative biliary atresia (11.1 SD 2.3%). Nine of 16 hepatitis patients had elevated C1q binding as compared with 1 of 16 with biliary atresia. The highest value for anti-LSP and C1q binding were found in sera from patients with histologically severe hepatitis and hepatitis associated with specific viral or bacterial causes. Anti-LSP was significantly raised 5 months post-operatively in all of 6 patients with biliary atresia and poor biliary drainage but only 2 of 5 survivors. Elevated C1q binding was detected in 6 of 7 with poor drainage and 1 of 7 survivors at the same stage. Anti-LSP and C1q binding fell in 4 patients with neonatal hepatitis on recovery. These findings suggest that immunological mechanisms, possibly involving antibody to hepatocyte membrane components and immune complexes, may be involved in the pathogenesis of progressive liver disease in biliary atresia.