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Biomedical subjects

M Kaye

Publications and source records attributed to M Kaye.

At least 19 recordsLinked to original sources
PubMed2006

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.

Adult↗
PubMed2004

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.

AIDS-Related Opportunistic Infections↗
PubMed2000

Acquired cystic kidney disease: rapid progression from small to enlarged kidneys simulating adult polycystic kidney disease.

A 57-year-old man on chronic hemodialysis presented marked bilateral renal enlargement due to acquired cystic kidney disease (ACKD). He had been on hemodialysis for less than 3 years only (14 months prior to receiving a functional renal transplant which lasted 8 years, followed by 18 additional months of dialysis), before the diagnosis of ACKD was made following an episode of flank pain with gross hematuria. The marked changes in kidney appearance during this 11-year period were documented by serial ultrasound examination showing the kidneys to be of near-normal size before the start of dialysis (> or =10 cm in 1986), then shrunken and contracted 5 years later while having a functioning renal transplant (<5 cm in 1991), and markedly enlarged reaching the size of adult polycystic kidney disease after returning to dialysis (>13 cm in 1997). Since the risk of ACKD increases with duration of dialysis, we sought additional predisposing factors in this unusual case and found that 2 years after renal transplantation, the patient was diagnosed with breast cancer for which he was treated with surgical excision and tamoxifen. Based on ultrasound evidence that the tamoxifen treatment preceeded the appearance of the renal cystic changes, we wonder whether this drug may have played a role in the rapid development of ACKD.

Antineoplastic Agents, Hormonal↗
PubMed2000

Metabolic acidosis during urinary retention in a patient with an enterovesical fistula.

We report a patient known to have an enterovesical fistula who presented severe acute metabolic acidosis during an episode of urinary retention. The enterovesical fistula which had been intermittently symptomatic for 4 years, had developed after several intestinal surgical procedures and related intraperitoneal sepsis following resection of colon cancer 21 years previously. The patient who had a total colectomy and ileostomy, was admitted for hip replacement with the routine placement of a Foley bladder catheter. Three weeks post-operatively, the patient developed acute urinary retention following removal of the urinary catheter. The output from his ileostomy was immediately markedly increased, presumably from bladder urine diverted into the intestines through the enterovesical fistula. Within a few days he presented a normal anion gap metabolic acidosis with raised urea and stable creatinine; his clinical status deteriorated markedly with profound obtundation. These metabolic abnormalities were readily corrected by re-insertion of the Foley catheter with restoration of normal urine flow and immediate corresponding fall in the ileostomy output. Radiographic studies showed the presence of the enterovesical fistula originating from the jejunum. This is the first report of acute metabolic acidosis in association with an enterovesical fistula; the severe metabolic disturbances were triggered by the development of urinary retention resulting in the diversion of urine into the small bowel through the fistula.

Acidosis↗
PubMed1998

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.

Aged↗
PubMed1998

The effect on blood pressure of an acute fall in ionized calcium during hemodialysis. A randomized study in two patients.

AIM: Elevating serum ionized calcium levels is known to stabilize blood pressure during and after a hemodialysis session. The data on lowering calcium levels is limited. SUBJECTS AND METHODS: This study examined the responses to an acute drop in ionized calcium during a four hour hemodialysis session in two subjects who differed in the presence (patient 1) or absence (patient 2) of anti-hypertensive medication and average weight loss of 4 kg (patient 1) or 2 kgs (patient 2) with each dialysis. Parathyroid hormone (PTH) levels were normal (patient 1) or very high (patient 2). A calcium free dialysate was used and the calcium infusion rate distal to the dialyzer was varied to produce either no change in ionized calcium for 10 dialyses, or a fall of at least 0.2 mmol/l for 10 dialyses. The sequence was randomized and was blinded to the observers and patients. RESULTS: The fall in ionized calcium was similar in each individual, 0.37 +/- 0.11 and 0.34 +/- 0.05 mmol/l. PTH rose from 8.6 +/- 1.6 to 24.2 +/- 6.6 pmol/l for patient 1 and 144.6 +/- 59.9 to 234.8 +/- 32.3 pmol/l for patient 2: patient 1 showed a fall in blood pressure after dialysis associated with the fall in calcium. This was most pronounced in the upright position whereas there was no change for Patient 2. For Patient 1 standing mean blood pressure post-dialysis was 104 +/- 6 mmHg when the calcium was stable and 94 +/- 10 mmHg with hypocalcemia p <0.01. Mean blood pressure during dialysis was also lower with hypocalcemia 100 +/- 7 versus 92 +/- 9 p <0.05. There were no significant changes in blood pressure for patient 2. Neither of the patients had any symptoms attributable to hypotension or hypocalcemia. CONCLUSION: It was concluded that modest falls in ionized calcium were associated with a drop in standing blood pressure only when combined with other factors predisposing to vascular instability. Even so these decreases were small enough to be asymptomatic.

Adult↗
PubMed1997

Hypocalcemic tetany and metabolic alkalosis in a dialysis patient: an unusual event.

The case is described of a 29-year-old man with renal failure and recurrent hyperparathyroidism who 3 weeks postparathyroidectomy developed hypocalcemic tetany because he was taking one-half the prescribed dose of calcitriol. He interpreted his symptoms as those of potassium intoxication and self-administered almost 1,500 mEq sodium bicarbonate. The increase in plasma sodium and osmolarity led to increased fluid intake, and at presentation he had an ionized calcium of 0.50 mmol/L, K 5.3 mmol/L, Na 148 mmol/L, total CO2 52.6 mmol/L, pO2 51.2 mm Hg, and pH of 7.61. He had gained 7 kg in weight. All abnormalities were corrected by dialysis, using initially a calcium-free dialyzate with extra calcium infused. The case illustrates the effect of alkalosis in reducing the amount of calcium that exists in ionized form, and it is suggested that complexing of calcium as calcium bicarbonate together with the pH change contributed to the decrease in ionized calcium. It is also an example of the hazards of treating patients who devise their own therapeutic regimens.

Adult↗
PubMed1996

Perceptual learning of stereoacuity.

It has often been noted that with repeated exposure to random-dot stereograms the time required to perceived depth decreases. Further, with extensive practice, stereoacuity thresholds have been shown to decrease. For both types of learning some researchers have reported specificity of the improvements to retinal location, and have thus suggested that the learning may be localised at early levels of visual processing, such as in primary visual cortex. However, these studies have not adequately ruled out the possibility that the specificity shown may be due to the operation of selective-spatial-attention mechanisms. In the present study this possibility was examined by training observers to judge the relative depth of a pair of stereograms presented equally often in two spatial locations, but stimuli were only presented with one direction of disparity (ie crossed or uncrossed) in any one location. Results indicated that, as expected, observers' judgements improved with practice. However, this improvement transferred completely to stimuli presented with the other direction of disparity in each location. Thus, it is argued that previous findings of retinal-location-specific improvements in stereoacuity may well be due to selective-spatial-attention mechanisms, rather than to learning localised at an early level of visual processing.

Adult↗
PubMed1995

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.

Animals↗
PubMed1995

Hypocalcemia after an acute phosphate load is secondary to reduced calcium efflux from bone: studies in patients with minimal renal function and varying parathyroid activity.

Seven patients with severe hyperparathyroidism secondary to chronic renal failure, six patients with hypoparathyroidism after remote total parathyroidectomy also with chronic renal failure, and a miscellaneous group of three patients, some of whom were in the previous two groups, were studied on 24 occasions over a 6-h period. Each test consisted of a 2-h control period followed by a 4-h phosphate (Pi) infusion period. Radioactive calcium, 45Ca, had been administered the evening before. Samples were taken every 15 min throughout the 6-h study. In all tests, ionized and total calcium fell as Pi rose. Intact parathyroid hormone levels (PTH) rose, except in the hypoparathyroid patients, in whom there was no change. The decline in 45Ca activity was not affected by the Pi infusion, the fall being -0.131 +/- 0.057 cpm/min during the control period and -0.124 +/- 0.043 during the Pi infusion. There were no changes in pH, bicarbonate, electrolytes, or vitamin D metabolites during the procedure. The mean overall fall in total calcium was -0.118 mmol/mmol rise in Pi. For ionized calcium, it was -0.067 mmol/mmol Pi or 56.8% of the total calcium. This ratio was unchanged throughout the test period. With a steady flux of calcium from extracellular fluid (ECF) to bone as measured by 45Ca, the fall in ECF calcium has to be due to a decreased flux from bone to ECF. This could be produced by the reduced dissolution of a labile pool of a calcium salt such as brushite, CaHPO4.

Adult↗
PubMed1994

Dialysate calcium loss using a calcium free dialysate.

Using a dialysate that contained no calcium, we studied the amount of calcium lost and the clearances of urea, creatinine, phosphate and calcium in fifteen different dialyzers at blood flow/min (QB) of 200 and 300. Five of these dialyzers, covering the functional range of the fifteen, were also tested at QB of 100, 150 and 400. The collection period was divided into the first twenty minutes and the remaining 220 minutes. Clearance was calculated using the initial twenty minutes and for all dialyzers the creatinine, phosphate and calcium clearances were linearly related to the measured urea clearance, r = 0.946, 0.810 and 0.808 respectively. Calcium recovered in the dialysate varied, depending on the dialyzer and QB, however the amount found plateaued at QB 200 and did not increase further, unlike creatinine, phosphate and urea. Total dialysate calcium loss for a four-hour dialysis averaged 49.9 mmol (range 42.2-63) or almost 2g of elemental calcium for QB of 200 ml/min and 48.9 mmol (range 31.1-65.5) or 1.95 g of elemental calcium for a QB of 300 ml/min. Decreasing the calcium infusion replacement rate did not decrease the calcium dialysate loss in equal amounts as the blood to dialysate gradient falls leading to a smaller than expected dialysate loss. Measured urea clearance in these fifteen dialyzers was approximately 20% less than specified by the manufacturer and almost 30% less for creatinine and phosphate. This difference is probably due to in vivo measurements with blood whereas most of the specifications are obtained using saline in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1994

A study on the reliability of dipstick urinalysis.

The objective of this study is to determine the reliability of the Ames automated method as a screening procedure for the detection of red blood cells and leukocytes. 5486 urines were analyzed by an automated dipstick technique. 3127 urines were completely negative on the stick and 2359 showed a positive finding. All 2359 dipstick positive urines and 456 of the 3127 dipstick negative urines (total of 2815) were read blindly by one of two nephrologists working on different days, 1743 by M. K. and 1072 by P. S. Red cells, leukocytes and casts were enumerated per high power field and compared to the dipstick findings. Urines that were negative by dipstick for protein, blood leukocytes, nitrites, glucose and ketones were generally negative on microscopic examination, with only 5.3% having any abnormality. Urines positive for one or more of these findings correlated poorly with the microscopic findings due to the number of false positive and false negative dipsticks for red cells and leukocytes. Sensitivities were 75.3% and 81.0% and specificities were 88.6% and 64.3%, for red cell and leukocytes, respectively. Increasing the dipstick cutoff point improved sensitivity but lowered specificity. Urines positive for glucose and ketones had lower sensitivities for the detection of leukocytes, but not urines positive for protein. Microscopic examination should be done on dipstick abnormal urines. This may not be necessary for negative urines unless specifically indicated for clinical reasons. Urines positive for ketones or glucose should be screened systematically since they give a larger proportion of false negatives for leukocytes.

Female↗
PubMed1993

Long-term studies using a calcium-free dialysate.

In this prospective controlled study the purpose was to assess the long-term safety of calcium-free dialysate (O Ca) for hemodialysis and to determine the optimum calcium replacement. With this technique there is no calcium in the dialysate and calcium is infused into the drip chamber distal to the dialyzer. We compared the use of a standard bicarbonate dialysate with a calcium free dialysate in two groups of patients. One group (study 1) received 10 mmol/hour Ca replacement, the other (study 2) received 13.3 mmol/hour Ca during dialysis. Each O Ca period lasted six months. This experimental period was compared with the six months preceding and following in the same patient and as well, with a concurrent control group who received standard bicarbonate dialysis either with 1.5 mmol/l calcium in the dialysate in study 1 or 1.75 mmol/l in study 2. Each group had nine to eleven subjects. No adverse effects were seen in either of the studies. With 10 mmol/hour calcium replacement there was a small but not significant rise in the pre-dialysis intact parathyroid hormone level (PTH) whereas in all the other groups it remained the same or fell. There was significantly less rise in the post-dialysis calcium in the same group and this was associated with a small but not significant fall in both pre-dialysis total and ionized calcium. It was concluded that the O Ca technique can be used for long periods and that 13.3 mmol/hour is a satisfactory replacement using Discap 140 dialyzers or their equivalent.

Bicarbonates↗
PubMed1993

Calcium metabolism in acute renal failure due to rhabdomyolysis.

We report a patient with drug and hyperthermia induced rhabdomyolysis who developed acute renal failure. During the oliguric phase of 22 days, there was profound hypocalcemia (lowest ionized calcium of 0.34 mmol/l), associated with appropriately elevated intact PTH levels and high normal 1,25(OH)2D levels. Massive calcification in necrotic muscle occurred during this time. In the recovery phase, hypercalcemia was present lasting 33 days (maximum ionized calcium of 1.99 mmol/L), associated with suppression of PTH secretion, low 1,25(OH)2D3 levels, decreased bone resorption and mobilization of the muscle calcium deposits. This case report illustrates that the changes in serum calcium in rhabdomyolysis-associated acute renal failure are explicable by the deposition or removal of mineral into or from necrotic muscle with the parathyroid and vitamin D changes occurring secondarily.

Acute Kidney Injury↗