First Report of Pepino mosaic virus Infecting Tomato in South Africa.

Pepino mosaic virus (PepMV) (genus Potexvirus) is a highly infectious virus that is responsible for significant losses in yield of tomato fruit (Solanum lycopersicum) across Europe, Asia, and the Americas in the last decade (1). During the winter growing season of 2008, uneven discoloration of tomato fruit from farms in Limpopo Province, South Africa, was detected at the Pretoria fresh produce market. Twenty fruit were randomly selected from five different suppliers in this region and the 100 samples were batched into subsamples of five fruit. Leaves with suspect mosaic and bubbling symptoms were also detected from farms in Limpopo and were thus sampled. Leaf and fruit samples were tested by double antibody-sandwich (DAS)-ELISA (2) using polyclonal antibodies against PepMV (Agdia, Elkhart, IN) combined with appropriate positive and negative controls. Fruit samples from two of the suppliers, and all leaf samples tested, reacted strongly with PepMV antibodies. Inoculum was prepared from pooled DAS-ELISA-positive leaf samples and inoculated onto 10, 4-week-old, susceptible S. lycopersicum cv. Rooikhaki seedlings. After 3 weeks, all inoculated plants had developed characteristic PepMV symptoms (2) including leaf bubbling, distortion, and curled leaves. Older leaves developed yellow spots and light/dark green leaf mosaic while apical regions were stunted and branches were distorted to form 'nettle-head' symptoms. Fruit surfaces were marbled or displayed flaming and uneven discoloration. Leaves from symptomatic plants were sampled for confirmation of PepMV infection by DAS-ELISA and all samples reacted positively with PepMV antibodies. Total RNA was extracted from 500-µg replicates of pooled leaf samples from infected plants with the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany), and amplified by conventional two-step reverse-transcription-PCR using a PepMV-specific primer set: Ker 1 (2) and PepCP-R (4) for a 986-bp region, including the coat protein, of the PepMV genome. PCR products were cloned into pTZ57R/T vector (Fermentas, Vilnius, Lithuania [UAB]) and six clones were purified and sequenced using universal M13 primers (3). Phylogenetic analysis clustered the sequence with EU (European), LP (Peruvian), US1 (United States)/CH1 (Chilean) and US2/CH2 PepMV isolates. The PepMV isolate accessions for US2/CH2 (AY509927, FJ612601, EF408821, FJ212288, and DQ000985) were identified as the closest relatives based on 98 to 99% nucleotide similarity obtained using BLASTN. The coat protein sequence of the South African isolate was submitted to GenBank (Accession No. HQ872607). To our knowledge, this is the first confirmed report of PepMV in South Africa. Further studies are necessary to determine its incidence and spread in this country. The presence of PepMV signals the urgent need for adoption of appropriate phytosanitary measures to restrict the spread and impact of this virus. References: (1) I. M. Hanssen and B. P. H. J. Thomma. Mol. Plant Pathol. 11:179, 2010. (2) I. M. Hanssen et al. Plant Pathol. 58:450, 2009. (3) J. Messing. Method Enzymol. 101:20, 1983. (4) I. Pagán et al. Phytopathology 96:274, 2006.

Calcium metabolism following renal transplantation.

Abnormalities of calcium homeostasis are a recognized feature of end-stage renal disease. The treatment of choice is renal transplantation, but this does not always result in normalization of the biochemical profile. Persistent hypercalcaemia is well documented and our study was undertaken to investigate the status of the calcium regulating hormones in renal patients post-transplantation. Serum calcium, parathyroid hormone, 1,25-dihydroxyvitamin D (1,25(OH)2D) and osteocalcin concentrations were measured in post-transplant patients. Twenty per cent of the patients had subnormal 1,25(OH)2D concentrations while 55% had biochemical evidence of hyperparathyroidism but only 5% were hypercalcaemic. Time elapsed since transplantation was not correlated with any of the analytes investigated and there was no relationship between persistent impairment of renal function and abnormalities of calcium homeostasis.

Effect of chronic low-dose arginine vasopressin infusion on body fluid homoeostasis during adaptation from a high- to a low-sodium diet in normal man.

1. A diuresis occurs within the first 36h of salt restriction. A decline in plasma arginine vasopressin concentration may contribute to both the diuresis and antinatriuresis. 2. We have studied six normal human subjects during 36h of dietary sodium restriction. In one study subjects received an intravenous infusion of D-glucose, and in the other an infusion of arginine vasopressin (6 fmol min-1 kg-1). 3. In the D-glucose phase plasma arginine vasopressin concentration fell (1.77 +/- 0.34 to 1.02 +/- 0.13 pg/ml), urine flow increased (67.9 +/- 11.5 to 89.8 +/- 17.1 ml/h), haemoconcentration occurred (packed cell volume 40.8 +/- 0.3 to 42.8 +/- 0.5%, protein concentration 71.6 +/- 0.5 to 74.5 +/- 0.6 g/l), plasma sodium concentration fell (140 +/- 0.2 to 138 +/- 0.2 mmol/l) and plasma renin activity increased (1600 +/- 153 to 3700 +/- 356 pg of angiotensin I h-1 ml-1). 4. In the arginine vasopressin phase plasma arginine vasopressin concentration remained constant (1.5 +/- 0.13 to 1.34 +/- 0.11 pg/ml), the diuresis was reversed (65.7 +/- 9.9 to 52.1 +/- 8.9 ml/h), plasma sodium concentration fell further (139.8 +/- 0.4 to 136.1 +/- 0.4 mmol/l), the rise in plasma renin activity was reduced (arginine vasopressin 2552 +/- 292; D-glucose, 3700 +/- 356 pg of angiotensin I h-1 ml-1) and creatinine clearance was lower in the last 12h of salt restriction (arginine vasopressin, 96.1 +/- 6.9; D-glucose 116.5 +/- 6.8 ml/min). Renal sodium excretion was unaffected by arginine vasopressin infusion. 5. We conclude that the fall in plasma arginine vasopressin concentration during dietary salt restriction, whilst not affecting renal sodium excretion, may be important in the regulation of plasma sodium concentration, plasma renin activity and glomerular filtration.

'Low sodium' diuresis and ileal loss in patients with ileostomies: effect of desmopressin.

Patients with ileostomies show an early diuresis when sodium restricted; this, together with an obligatory ileal sodium loss, predisposes them to severe salt and water depletion. The role of arginine vasopressin in this circumstance and whether it is natriuretic, or antinatriuretic, is unclear. There is also controversy over its likely effect on small bowel fluid reabsorption. We have examined the effect of the non-pressor (V2) synthetic vasopressin analogue 1-deamino-8-D-arginine (desmopressin) on renal and ileal sodium and water excretion in ileostomy patients during acute adaptation to a low sodium diet. Patients were studied on two separate occasions (nonrandomised) with and without the administration of desmopressin (0.75 micrograms intramuscular, three times a day). In eight subjects without desmopressin there was pronounced diuresis on the first low sodium day, associated with a fall in renal sodium excretion and no change in ileal output or composition. In five (of the original) subjects with desmopressin there was pronounced antidiuresis, no change in renal sodium excretion, and no change in ileal output or composition. In both studies rises in plasma renin activity and salivary aldosterone concentration lagged behind the early decline in renal sodium excretion. We have confirmed the phenomenon of 'low sodium' diuresis after sodium restriction in ileostomy patients and shown that it can be prevented by desmopressin. Desmopressin has no direct or indirect effect on renal sodium excretion or ileal fluid and electrolyte loss in humans.

Studies of circulating parathyroid hormone following parathyroidectomy in renal osteodystrophy.

A study has been undertaken to document in detail some of the changes that occur following parathyroidectomy in chronic renal failure patients. In an attempt to predict more precisely the timing of the post-operative hypocalcaemia, serum parathyroid hormone (PTH) concentrations were measured in six patients with renal osteodystrophy undergoing subtotal parathyroidectomy [5] and total parathyroidectomy [1]. The values obtained were related to post-operative changes in serum calcium and albumin concentrations. The intact-PTH concentration in serum was shown to decline rapidly post-operatively while the C-terminal PTH followed a more gradual course. Neither total nor ionised serum calcium concentrations exhibited a correspondingly dramatic fall after parathyroidectomy and the serum albumin concentration remained unaltered.

Time-course and relationship of the early changes in renal sodium excretion and aldosterone secretion during dietary sodium restriction in normal man.

1. The fall in renal sodium excretion after dietary sodium restriction is prompt and reproducible. The importance of increased aldosterone secretion during the early phase (within 48 h) of this response is unclear. Using two indirect measures of aldosterone secretion (in urine and saliva), we have tried to relate changes in excretion and concentration of this hormone to renal sodium excretion during the abrupt transition from a normal (approximately 150 mmol/day) or high (260 mmol/day) to a low (5-25 mmol/day) sodium intake in 11 and seven male volunteers, respectively. 2. All subjects showed reduced renal sodium excretion within 36 h of dietary restriction, but the times at which increases in renal aldosterone excretion, saliva aldosterone concentration and plasma renin activity became statistically significant varied widely (8-72 h, 2.5- greater than 62.5 h and less than 4- greater than 38 h for renal aldosterone secretion, saliva aldosterone concentration and plasma renin activity, respectively). Circadian fluctuations in saliva aldosterone concentration were apparent and increased in amplitude during sodium restriction. 3. Urine flow rate tended to increase on the first day of sodium restriction and this reached statistical significance in the group initially on a high sodium intake (64.0 +/- 8.8 to 84.3 +/- 11.2 ml/h, P less than 0.01); although the pattern of urine flow did correlate with plasma arginine vasopressin concentration (r = -0.49, P less than 0.01), there was no significant decrease in mean plasma arginine vasopressin concentration [1.15 (0.92-1.44) to 0.90 (0.72-1.12) pmol/l, P = 0.08; geometric mean and 95% confidence limits].(ABSTRACT TRUNCATED AT 250 WORDS)

Selective defect in gonadotrophin secretion in patients with autonomic failure.

We studied the neuroendocrine effects of a condition associated with abnormal hypothalamic amines. Hypothalamo-anterior pituitary function was assessed in five male subjects with autonomic failure (AF) and in five age and sex-matched controls. All subjects showed normal gonadotrophin and TSH responses to GnRH and TRH, respectively. In control subjects, intravenous infusion of naloxone caused a significant rise in overall LH concentrations as well as increased frequency and amplitude of LH pulses. In contrast, in AF subjects naloxone did not alter LH concentrations or increase LH pulse frequency. Naloxone also caused an increase in neurosecretory GH pulses not only in AF subjects but also in the controls. These results suggest that in man, ascending catecholamine pathways are important in the control of gonadotrophin secretion. The markedly different response of GH to an opioid antagonist in elderly subjects should be further investigated.

Diurnal fluctuation in saliva aldosterone concentration.

We have measured saliva aldosterone concentration (SA) at frequent intervals in subjects going about their normal daytime activities. Four hourly sampling sufficed to give a reasonable estimate of mean diurnal SA but hourly sampling is necessary if it is desired to study the temporal pattern of SA. In subjects with normal or elevated mean levels, SA fluctuated considerably suggestive of several distinct episodes of aldosterone secretion. Such fluctuations show little correlation with the concentrations in saliva of glucocorticoids (cortisol + cortisone) nor are they consistent with a circadian rhythm of aldosterone secretion. We suggest that they may represent responses to such stimuli as eating, drinking or physical activity, and possibly to other as yet unidentified factors. These observations show the importance of comprehensive diurnal assessment of aldosterone level in physiological and pathological investigations. Because of its non-invasive nature and the high productivity of the assay, measurement of SA is ideally suited for this purpose.

Active and inactive renin in anephric man: a comparison of molecular weight studies with normal human plasma and the effect of a specific monoclonal anti-renin antibody.

Measurements of active and inactive renin have been made in a group of six anephric patients and in 30 normal healthy volunteers. Plasma renin activity (PRA) was detected in all of the anephric patients but values were below the normal range. A trypsin-activatable totally inactive renin was present in the plasma of all six patients. In three patients, levels of inactive renin were greater than that found for the mean value of the control group. Gel filtration studies of anephric plasma revealed a degree of heterogeneity of molecular forms of active high molecular weight (HMW) renin. However, an active form of approximately 65,000 daltons was usually present. Inactive renin, partially purified from anephric plasma had an apparent molecular weight (MW) of 59,000 daltons. Affinity chromatography with H.77 Sepharose was used to purify active renin from anephric and normal plasma following treatment with trypsin. The increased PRA in plasma from both groups following trypsin was associated with a 56,000 daltons form indicating little, if any, change in MW upon activation. The active HMW forms and the activated inactive renin were all totally inhibited by a renin-specific monoclonal antibody raised against human kidney renin.

Tuberculosis in renal failure: a high incidence in patients born in the Third World.

We report 11 cases of tuberculosis among patients with chronic renal failure being treated in our unit. All were born outside the United Kingdom, and represent 25% of the non-europid patients in the unit. This is about a seventy-fold increased incidence of tuberculosis in this group. Diagnosis is difficult and mortality high if the diagnosis is delayed. Culture of tissue biopsies is the most reliable investigation and chemotherapy should be commenced promptly or a therapeutic trial considered in doubtful cases. Chemoprophylaxis may be beneficial in patients from these ethnic groups or in any uremic patient with evidence of old tuberculosis. Three patients with advanced disease died despite antibiotic treatment, but in the remainder, triple therapy with normal doses of rifampicin, isoniazid and pyrazinamide proved safe and effective.

Detection and investigation of renal artery stenosis.

A retrospective analysis was done on 235 hypertensive patients undergoing renal arteriography. Of the 85 patients with renal artery stenosis 50 underwent 56 operations or angioplasties and have been followed up for at least a year. 41 (73%) of these procedures were curative or led to improved blood-pressure control. These results make it worthwhile identifying hypertensive patients with renal artery stenosis who may benefit from surgery or angioplasty. Vascular disease, epigastric bruit, and impaired renal function were commoner in the renal artery stenosis patients than in the 81 with normal arteriograms, but there were no features pathognomonic of stenosis. Intravenous urography had a sensitivity of 83% and a specificity of 69.5% in identifying renal artery stenosis; those for isotope renography were 90.5% and 38.5%, respectively. Divided renal vein renins did not predict the outcome of intervention. Arteriography should, if there are no contraindications to intervention, be the first and definitive investigation when renal artery stenosis is suspected--for instance, in hypertensive patients with accelerated or malignant hypertension, those whose blood pressure is poorly controlled by multiple therapy, and those who have had recent deterioration in blood-pressure control or renal function.

Kaposi's sarcoma of the bowel--presenting as apparent ulcerative colitis.

Persistent diarrhoea with mucus-production developed in a 37 year homosexual man, and an initial diagnosis of ulcerative colitis was made after barium enema examination and rectal biopsy. The patient later developed cutaneous lesions which proved to be Kaposi's sarcoma, and the bowel lesion was also subsequently shown to be Kaposi's sarcoma. This tumour occurred as a manifestation of the acquired immune deficiency syndrome (AIDS). The patient was treated with alpha interferon, with partial regression of the skin lesions, but progression of the bowel tumour. Because of severe bowel symptoms, including episodes of subacute intestinal obstruction, the localised bowel disease was treated with radiotherapy. In view of the increasing incidence of AIDS, a diagnosis of Kaposi's sarcoma must be considered in homosexual men presenting with persistent diarrhoea, for which no infectious cause can be demonstrated.

Clinical aspects of the acquired immune deficiency syndrome in the United Kingdom.

Between August and November 1983, seven new patients with AIDS were seen at this hospital; two with disseminated Kaposi's sarcoma, and five with opportunist infections, of whom three have died. We present the case histories of the five patients with opportunist infections, which show the wide clinical range of AIDS and suggest that the pattern of infection in the UK may differ from that reported in the USA.

Sinus node function in first three weeks after cardiac transplantation.

Donor sinus node function was studied in 10 patients from day 4 to day 24 after cardiac transplantation. Cycle length, atrial arrhythmias, corrected sinus node recovery time, and estimated sinoatrial conduction time were recorded daily. Five patients had at least two sets of results suggesting sinus node dysfunction (group A) while five patients had no such abnormalities (group B). The prognosis in group A was poor, with four of the five patients dying within four months of the operation; one unexpected death from arrhythmias was recorded by ambulatory electrocardiographic monitoring. All five patients in group B survived for at least eight months. In nine patients sinus node function varied from day to day, with corrected sinus node recovery time reaching a peak at 11 to 18 days after operation. The longest corrected sinus node recovery time was 11 160 ms. Neither the differences between the patients, nor the day to day variation, could be explained solely by the degree of rejection as assessed by biopsy or by the ischaemia time of the heart during procurement. Sinus node dysfunction soon after transplantation is associated with a poorer prognosis and might be the terminal event in some cases.