SARS-associated coronavirus replication in cell lines

Given the potential for laboratory-associated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) infections, we must know which cell lines are susceptible to the virus. We investigated 21 cell lines routinely used for virus isolation or research. After infection with SARS-CoV, cells were observed for cytopathic effects, and quantitative real-time polymerase chain reaction was used to measure ongoing viral replication. An indirect immunofluorescence assay was also used as a confirmatory test. The study identified 10 new cell lines capable of supporting the replication of SARS-CoV and confirmed the susceptibility of 4 cell lines previously reported. This study shows that SARS-CoV can be isolated in several cell lines commonly used for diagnostic or research purposes. It also shows that SARS-CoV can achieve high titers in several cell lines, sometimes in the absence of specific cytopathic effects.

HIV and hepatitis C coinfection within the CAESAR study

The declining incidence of AIDS-related opportunistic diseases among people with HIV infection has shifted the focus of clinical management to prevention and treatment of comorbidities such as chronic liver disease. The increased risk of hepatitis C virus (HCV)-related advanced liver disease in people with HIV infection makes early HCV diagnosis a priority. To assess HCV prevalence and predictors of HIV/HCV coinfection, we have conducted a retrospective analysis of people enrolled in the CAESAR (Canada, Australia, Europe, South Africa) study, a multinational randomized placebo-controlled study of the addition of lamivudine to background antiretroviral therapy. The impact of HCV on HIV disease progression was also examined. Anti-HCV antibody testing on 1649 CAESAR study participants demonstrated a HIV/HCV coinfection prevalence of 16.1%, which varied from 1.9% in South Africa to 48.6% in Italy. The strongest predictor of HIV/HCV coinfection was HIV exposure category (P<0.0001), with odds ratios (ORs) compared to homosexual as follows: injecting drug use (IDU), 365 [95% confidence interval (CI): 179-742]; transfusion or blood products, 32.2 (95% CI: 15.2-67.6); homosexual and IDU, 22.9 (95% CI: 8.5-62.1). The prevalence of HIV/HCV was low (3.7%) among homosexual men without reported IDU. Other predictors of HIV/HCV coinfection were alanine aminotransferase (ALT), country of residence, ethnicity and stage of HIV disease. A history of IDU or ALT > or =40 U/L at baseline had a positive predictive value (PPV) of 35%, negative predictive value (NPV) of 96%, sensitivity of 82% and specificity of 71% for HIV/HCV coinfection. HIV disease progression was similar in HIV monoinfected and HIV/HCV coinfected patients. People with HIV and a history of IDU or elevated liver function tests should be targeted for HCV testing. The low prevalence of HIV/HCV coinfection among homosexual men without a history of IDU suggests low efficiency of sexual HCV transmission.

Laboratory diagnosis and surveillance of human respiratory viruses by PCR in Victoria, Australia, 2002-2003

Respiratory viruses were identified by the polymerase chain reaction (PCR) in more than 4,200 specimens collected during 2002 and 2003 in Victoria, Australia from patients admitted to hospitals or participating in an influenza surveillance program. Influenza viruses and picornaviruses were important causes of morbidity in both years. Additional testing of picornavirus‐positive samples suggested that rhinoviruses but not enteroviruses were more likely to be associated with respiratory symptoms, irrespective of the season in which they circulated. Detection of influenza viruses was strongly associated with the clinical symptoms of cough, fever, and fatigue; but each of the other respiratory viruses occasionally caused these symptoms or was responsible for symptoms severe enough to require hospitalization. Human coronaviruses HCoV‐OC43 and HCoV‐229E circulated at low levels throughout the study period with peak activity in winter, but overall did not circulate as widely as has often been reported for these agents. Evidence for the human metapneumovirus (hMPV) was only sought in the second year of the study and revealed low‐level circulation of this virus, mainly in the cooler months among the very young and adult populations. The detection rate of all viruses declined with increasing age of the patient, particularly in hospital patients. Infection with more than one respiratory virus occurred in a small number of patients; picornaviruses were most commonly implicated in these dual infections. J. Med. Virol. 75:122–129, 2005. © 2005 Wiley‐Liss, Inc.

Alterations in colonic anatomy induced by chronic stimulant laxatives: the cathartic colon revisited

Cathartic colon is a historic term for the anatomic alteration of the colon secondary to chronic stimulant laxative use. Because some have questioned whether this is a real entity, we investigated changes occurring on barium enema in patients ingesting stimulant laxatives. Our study consisted of two parts. In part 1, a retrospective review of consecutive barium enemas performed on two groups of patients with chronic constipation (group 1, stimulant laxative use [n=29]; group 2, no stimulant laxative use [n=26]) was presented to a radiologist who was blinded to the patient group. A data sheet containing classic descriptions of cathartic colon was completed for each study. Chronic stimulant laxative use was defined as stimulant laxative ingestion more than three times per week for 1 year or longer. To confirm the findings of the retrospective study, 18 consecutive patients who were chronic stimulant laxative users underwent barium enema examination, and data sheets for cathartic colon were completed by another radiologist (part 2). Colonic redundancy (group 1, 34.5%; group 2, 19.2%) and dilatation (group 1, 44.8%; group 2, 23.1%) were frequent radiographic findings in both patient groups and were not significantly different in the two groups. Loss of haustral folds, however, was a common finding in group 1 (27.6%) but was not seen in group 2 (p < 0.005). Loss of haustral markings occurred in 15 (40.5%) of the total stimulant laxative users in the two parts of the study and was seen in the left colon of 6 (40%) patients, in the right colon of 2 (13.3%) patients, in the transverse colon of 5 (33.3%) patients, and in the entire colon of 2 (13.3%) patients. Loss of haustra was seen in patients chronically ingesting bisacodyl, phenolpthalein, senna, and casanthranol. We conclude that long-term stimulant laxative use results in anatomic changes in the colon characterized by loss of haustral folds, a finding that suggests neuronal injury or damage to colonic longitudinal musculature caused by these agents.

Elective total parathyroidectomy without autotransplant in end-stage renal disease

Ten patients are reported following parathyroidectomy (PTX). In 9 all identifiable parathyroid tissue in the neck was deliberately removed, and in the tenth (operated 14 years ago) the remnant which had been left probably did not function. Their post-operative course resembled that of patients treated conventionally, and their subsequent course was likewise uneventful with disappearance of all symptoms associated with their osteodystrophy. All patients required oral calcium supplementation but none were given vitamin D compounds after the initial period of repletion following surgery. Mean serum values were (before PTX and current) for calcium 2.63 +/- 0.14 and 2.33 +/- 0.08 mmol/liter, P = NS, for phosphorus 1.96 +/- 0.13 and 1.38 +/- 0.09 mmol/liter, P less than 0.01, and for alkaline phosphatase 713 +/- 191 and 101 +/- 14 IU, P less than 0.05. Evidence for residual parathyroid tissue was present in each case; one patient remained mildly hyperparathyroid and several were mildly hypoparathyroid by the IRMA PTH assay. Bone histomorphometry in five subjects post-PTX showed either normal or low turnover. Radiologically, striking remineralization was seen with disappearance of all erosive changes. We suggest that residual areas of parathyroid tissue are stimulated and continue to secrete hormone even when all the discrete glands have been removed. It is recommended that when indicated, and in the absence of aluminum excess, total PTX without autotransplant should be the preferred form of therapy for long-term dialysis patients.

Resistance to parathyroid hormone in renal failure: role of vitamin D metabolites

Resistance to the calcemic action of parathyroid extract (PTE) was shown in thyroparathyroidectomized rats after 5 hr of renal failure that was induced by either bilateral nephrectomy (NPX) or ureter ligation (UL). Studies were carried out to investigate the relationship of parathyroid resistance to the vitamin D status of the animal. Concentrations of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 24,25-dihydroxycholecalciferol (24,25(OH)2D3) were similar in pooled sera samples from rats either UL or sham-operated and treated with PTE. Pretreatment with oral 25-hydroxycholecalciferol or with a combination of i.v. 24,25(OH)2D3 and 1,25(OH)2D3 prior to UL failed to alter the resistance. Resistance was also present in a group in vitamin-D-deficient rats. A similar group given 1 microgram of vitamin D2 showed more parathyroid resistance than did the group not given vitamin D2. In chronic renal failure of 28 day's duration, parathyroid resistance was again demonstrated, but, in contrast to the acute renal failure models, this was partly corrected by prior 1,25(OH)2D3 administration. These studies show that parathyroid resistance is not caused by an abnormality of vitamin D metabolism in the acute renal failure model, and we suggest that the phenomenon is due to the accumulation of one or more uremic factors.

When is it an osteoclast?

Using acid phosphatase as a marker, osteoclasts were examined from single sections of undemineralised iliac crest biopsies from patients with renal failure and from normal controls. Eighty one per cent of the cells from controls and 56% of the cells from patients with renal failure appeared to be non-nucleated or mononucleated. Serial sections showed, however, that 73% of the control cells were actually multinucleated as were 91% of the patients' cells. Howship's lacunae were present in similar proportions in the controls whether the cells were multinucleated or not, suggesting that they should all be classed as osteoclasts. More multinucleated cells and lacunae were present in the patients with renal failure. It is concluded that all acid phosphatase cells adjacent to bone are osteoclasts and that the presence of more lacunae and multinucleated cells in renal failure is compatible with enhanced cellular resorption.

Evidence that resistance to the calcemic action of parathyroid hormone in rats with acute uremia is caused by phosphate retention

An animal model was developed to examine the cause of resistance to the calcemic action of PTH in renal failure. Thyroparathyroidectomized (TPTX) rats were repeatedly reinfused with their excreted urine, over a 5-hour period, to produce an acute uremic animal with normal kidneys. Nonuremic controls were infused with equivalent volumes of a simple electrolyte solution. Using this model, we have demonstrated impaired calcemic response to PTH (Lilly Parathyroid Extract, 80 U/100 g) in urine-infused rats compared with electrolyte-infused rats. The final plasma calcium concentrations were 12.0 +/- 0.3 and 14.9 +/- 0.3 mg/dl, respectively (P less than 0.001). The cause of this impaired calcemic response was investigated by reinfusing rats with their own urine that had been pretreated with either activated charcoal or zirconium oxide in two different anionic forms, or urine that had been ultrafiltrated through an Amicon membrane of which the stated molecular-weight cut-off of the smallest pore-size membrane was 500 daltons. It was found that charcoal and ultrafiltration techniques had no effect, whereas the zirconium oxide treatment completely corrected the impaired calcemic response and returned the plasma phosphorus to a concentration similar to that in nonuremic controls. This can be explained by the fact that the principal effect of zirconium oxide on urine is to remove inorganic phosphate. Other groups of TPTX rats given PTH extract were infused with an electrolyte solution containing varying amounts of phosphate up to a maximum similar to the amount that a urine-infused rat would receive. A highly significant inverse relationship was found between the dose of phosphate infused with the electrolyte solution and the measured calcemic response to PTH. This relationship is represented by the following equation: calcium (mg/dl) = 14.84 - 0.139 inorganic phosphate; r = 0.915, P less than 0.001. From these series of studies, we conclude that phosphate retention is the cause of resistance to the calcemic action of PTH extract in this acute uremic model.

A study of vertebral bone powder from patients with chronic renal failure

Bone powder from patients dying with chronic renal failure of more than 1 yr duration was shown to release less calcium and more phosphate when equilibrated with a buffer solution. pH 7.4 at 4 degrees C. This change persisted after removal of the organic component and was associated with a reduction in the bone carbonate content. Crystal size and surface area showed no consistent changes from the controls and it was concluded that an alteration in the apatite crystal composition had occurred in long-standing uremia with carbonate-phosphate interchange. Support for this was provided by synthesis of apatites which were carbonate deficient and behaved in a similar manner to the uremic bones.

Observations on the mechanism of 99mTc-labeled phosphate complex uptake in metabolic bone disease

This communication describes a series of clinical and animal in vivo and in vitro investigations designed to elucidate the mechanism of 99mTc-Sn-phosphate complex concentration in metabolic bone disease. Rachitic and lathyritic animals were used as experimental models. Based on these studies it is concluded that 99mTc alters the pharmacology of the phosphate complexes, in particular pyrophosphate, which was the test agent most extensively employed, so that the usual affinity for mineral is for the greater part replaced by organic matrix binding. There is also evidence to suggest the immature collagen moiety of the organic matrix is the prime target of 99mTc-Sn-phosphate complex binding. Specifically, the aldehyde groups of the collagen molecule are suspected as being the major site of interaction.

Genetic lineage, bone mass, and physical activity in mice

Five strains of inbred mice were found to have variations in bone mass although they were similar in body weight. Two of these strains, C57BL/6J and A/J, were studied in greater detail and the former had more bone in both femur and tibia. The increased bone mass was associated with larger quadriceps muscles in the C57BL/6J animals when measured at 18 weeks of age. Activities of animals from these two strains were studied over 24 h periods using a cage with an ultrasonic movement detector and automatic counter. The C57BL/6J animals were more active than the A/J mice. The male C57BL/6J mice tended to have larger testicles and higher testosterone levels than the A/J animals, whereas the female A/J animals had larger ovaries and higher oestradiol levels. As both male and female C57BL/6J animals were more active, it was concluded that the sex hormone differences between the two strains was not responsible for either the changes in bone mass or physical activity. These findings indicate that in the mouse, activity is in part genetically determined. We have hypothesized that this, in turn, could affect muscle mass and secondarily, bone size and strength. If these results can be applied to humans, it would suggest that differences at birth between individuals are important for bone mass in later life and that muscle mass and activity are in part genetically influenced. If this was the case, then muscle mass and strength could be a factor in bone mass and one of the goals in prevention and treatment of osteoporosis should be directed toward preservation and/or augmentation of muscle strength.

Surveillance of respiratory virus infections in adult hospital admissions using rapid methods

Both influenza and respiratory syncytial virus (RSV) cause epidemics of respiratory illness of variable severity during the winter season. Influenza in particular has been blamed for hospital winter bed pressures, although it is thought that RSV may also play a role. Human metapneumovirus (hMPV) is a new respiratory virus reported to be important in children; only a limited number of studies are available for adult populations. We aimed to determine initially the burden of virologically confirmed infections, i.e. influenza, RSV and hMPV using polymerase chain reaction (PCR) technology and, in addition, to assess the feasibility of this approach as a surveillance tool for these respiratory viruses. Adult patients admitted to hospital in the previous 24 hours with onset of acute respiratory symptoms in the last 14 days were asked to participate. Informed written consent was obtained and nose and throat swabs taken. Multiplex PCR for influenza A (H1N1 and H3N2), influenza B and RSV A and B were carried out together with a separate PCR for hMPV. A total of 219 patients in 2001-2002 and 216 in 2002-2003 were tested and the combined results for both seasons were: 8 positive for influenza A/H1N1, 14 for influenza A/H3N2, 2 for influenza B, 14 for RSV A and 6 for RSV B. Most patients (261/435) were >65 years and most positives (30/44) were found within this age group. A number of patients aged >65 years who were positive for influenza (12/15) reported having had vaccine. In total, 373 samples were tested for hMPV and 20 were found positive across all age groups except the 45-54 years age group. As influenza activity was low during the study period the impact of infection on admissions could not be assessed. Nevertheless the viruses studied accounted for 15% of hospital admissions for respiratory infection. Most patients were aged >65 years, as expected. In the two years studied RSV and hMPV were each responsible for as many hospitalized cases of respiratory infection as influenza. Influenza infection must be considered even in those who give a history of vaccination. The molecular methods used in this study showed that surveillance of these respiratory viruses can be conducted and may help in the management of patients.

Depth perception, eye alignment and cortical ocular dominance of dark-related cats

On first exposure to light, animals that have been reared from birth until about 4 months of age in total darkness exhibit substantial visual and visuomotor deficits, which decline in severity during the first few months following exposure to light. In order to determine whether dark-reared animals eventually acquire stereoscopic vision following exposure to light we examined the binocular status of 5 dark-reared animals two of which developed convergent eye alignment. The binocular status was assessed behaviorally by measurements of the ability of each animal to perceive depth using either one or both eyes, and physiologically by documentation of the distribution of cortical ocular dominance of a sample of visual acuity, their binocular depth perception remained very poor, comparable to the monocular performance of normal cats. In marked contrast to normal animals none of the dark-reared animals, even those with normal eye alignment, performed substantially better binocularly than monocularly, a result indicating the absence of a uniquely binocular mechanism for depth perception in these animals. Although the dark-reared animals were found to retain a substantial (but reduced) complement of binocularly influenced cortical neurons, the tuning of these cells for retinal disparity must be insufficiently precise to mediate depth perception under binocular viewing conditions that is superior to that which can be achieved monocularly.

The effects in the rat of varying intakes of dietary calcium, phosphorus, and hydrogen ion on hyperparathyroidism due to chronic renal failure

Renal failure of 4 wk duration in rats led to parathyroid enlargement, increased bone resorption, and decreased tubular reabsorption of phosphate by the remnant kidney. The degree of hyperparathyroidism was influenced by each of the three dietary factors investigated. In the first study increasing calcium intake reduced the size of the parathyroids by increasing calcium and reducing phosphate absorption. In the second study phosphate intake was linearly related to parathyroid gland size in the uremic animals and associated with rising plasma phosphate levels. In the last study acidosis led directly to increased bone resorption but small parathyroid glands associated with elevated ionized calcium levels. Alkalosis lowered the serum ionized calcium and led to parathyroid enlargement and the expected associated findings. It was shown that parathyroid weight reflected both metabolic activity as judged by amino acid uptake, and the content of immunoassayable parathyroid hormone. In all studies gland weight was inversely related to serum ionized calcium.

Reasons for drinking: motivational patterns and alcohol use among college students

A principal components factor analysis of survey data from 393 college student drinkers (178 males) extracted four dimensions from a set of 16 reasons for drinking: avoidance, social, sensation seeking, and enjoyment. Motivational patterns and the relationships with alcohol use were examined with a canonical correlation analysis. Three significant canonical variates were found. The first variate contained students with high scores on all motivational factors. They were heavy drinkers with many alcohol-related problems. The second variate indicated that drinkers who drank primarily for enjoyment tended to be women who drank moderately. Male beer drinkers with strong sensation seeking motivations formed the third variate.

The calcium and vitamin D status in an elderly female population and their response to administered supplemental vitamin D3

Recent reports have implicated the importance of impaired calcium absorption, inadequate dietary vitamin D, and low serum vitamin D levels in the genesis of metabolic bone diseases in the elderly. This study evaluated the dietary intakes of calcium and Vitamin D, calcium absorption, and serum 25 hydroxycholecalciferol (25 OH D) levels in a population of women (mean age 83 yrs) compared to healthy volunteers (mean age 35 yrs). Dietary intakes of both calcium and vitamin D and serum 25 OH D levels were found to be comparable in both groups. Calcium absorption was normal in the subjects studied and did not change significantly after two 2-week periods of oral supplementation with vitamin D3 in doses of 500 I.U./day and 10,000 I.U./day, although the serum 25 OH D levels rose significantly and comparably in both groups. Thus other etiological factors may play relevant roles in the causation of bone diseases in the elderly and unless deficient dietary or serum vitamin D levels are demonstrated, empirical supplementation with vitamin D should not be undertaken. The differences of the above findings from previously published data are discussed.

HIV transmissions during seroconversion contribute significantly to new infections in men who have sex with men in Australia

Transmission of HIV from recently infected individuals contributes to the number of new cases of infection, but the extent to which it occurs from those who are unaware of their infection is not known. Phylogenetic analysis was performed on 209 cases of acute HIV subtype B infection detected between January 2005 and September 2010, most of whom (88%) were men who have sex with men. Only new cases with an evolving Western blot profile confirmed by detection of HIV RNA were included. Subjects whose known dates of seroconversion were within 1 month of at least one other phylogenetically linked case identified during the 6 years of the study were then examined to estimate the prevalence of onward transmission. Almost 30% of cases could have acquired their infection from another person undergoing seroconversion within the same month. Temporal increases in the number of phylogenetically related strains within several clusters were demonstrated during the study, although the rate of increase varied. Transmission of HIV from individuals undergoing seroconversion is an important contributor to the number of new infections identified every year and very likely occurs before they have knowledge of their infection. Clusters of related HIV strains can grow at a disconcerting rate, demonstrating that more focused public health efforts are required to minimize further HIV transmissions within sexual networks.