Biomedical subjects

L K Lloyd

Publications and source records attributed to L K Lloyd.

At least 37 records · Page 2Linked to original sources

PubMed1986

Year-to-year changes in effective renal plasma flow in asymptomatic spinal cord injury patients.

Year-to-year variations in effective renal plasma flow (ERPF) measurements were determined in 78 patients with spinal cord injury who had no urologic complications or surgery or bouts of chills and fever between consecutive annual follow-up examinations. The effects of age, gender, level and degree of lesion, and time since injury on the degree of variability were also determined. None of the factors considered had a statistically significant effect (P greater than 0.05) on year-to-year variations in ERPF. About 90 per cent of the individual kidney ERPF measurements were within 100 ml/min of the measurement made in the previous year, and 90 per cent of the total ERPF measurements were within 175 ml/min of the previous year's measurement. Follow-up of patients whose year-to-year variability exceeded these limits showed that most subsequently regressed toward the mean spontaneously. These data suggest that kidney blood flow varies considerably from year to year in otherwise healthy patients with spinal cord injury and that changes of 100 ml/min or more for an individual kidney or 175 ml/min or more for both kidneys together are common, but probably of little clinical significance, provided the absolute levels of ERPF remain within normal limits.

Adult↗

PubMed1986

Iatrogenic dilatation of the upper urinary tract during radiographic evaluation of patients with spinal cord injury.

Patients with upper and lower motor neuron spinal cord injuries were observed to determine whether cystography immediately before excretory urography induced iatrogenic dilatation of the upper urinary tract that was indistinguishable from true pathological dilatation. Evidence is given that such dilatation occurs. This iatrogenic dilatation is not seen in patients with normally innervated urinary tracts and appears to be caused by exaggerated bladder reflexes in patients with upper motor neuron lesions. Bladder spasms precipitated by cystographic contrast material also may create vesicoureteral obstruction and lead to dilatation of the upper urinary tract. Consequently, it is suggested that cystography should not immediately precede excretory urography. When such a sequence is necessary, room or body temperature contrast medium should be used for the cystogram, the bladder should be emptied before the excretory urogram is started and a 1-hour interval should be allowed between the 2 procedures. The findings also suggest that any factors that induce repeated or continuing bladder spasms may contribute to progressive dilatation of the upper urinary tract.

Contrast Media↗

PubMed1986

Initial bladder management in spinal cord injury: does it make a difference?

We classified 204 patients with acute spinal cord injury into 1 of 5 groups according to the initial form of urological management. Group A patients were placed on an intermittent catheterization program within 36 hours of injury, group B received a suprapubic trocar within 36 hours of injury, group C had urethral catheters in place for more than 36 hours before intermittent catheterization was begun, group D was on indwelling urethral catheter drainage throughout the hospitalization and discharged from the hospital with indwelling catheters, and group E was placed on intermittent catheterization in a community hospital. There were no statistically significant differences among the groups in the incidence of chills and fever, rate of urinary infections (excluding group D), incidence of upper tract changes, genitourinary complications or frequency of urological procedures at 1 year after injury. We conclude that the method of initial bladder management is relatively unimportant in determining the urological prognosis after spinal cord injury.

Adolescent↗

PubMed1986

New trends in urologic management of spinal cord injured patients.

We have attempted to address some of the current issues and new trends in the urologic management of SCI patients. Although tremendous progress has been made with these patients, resulting in a significant lowering of renal morbidity and mortality, there is still room for improvement. Newer methods of bladder management and refinements of older techniques are being sought. Progress in treating urinary infections should occur through development of new antibacterials and through improved understanding of host-bacterial interactions. Research into these problems and the general management of the neurologic dysfunction in SCI offers the hope of an even brighter future for these severely disabled patients.

Female↗

PubMed1986

Clinical significance of minimal changes on intravenous urography after spinal cord injury.

Evidence is given to support the thesis that minimal pyelocaliectasis and ureterectasis are of little clinical significance in spinal cord injured patients. Such renal changes almost always improve or remain stable on sequential examinations. Since moderate or severe pyelocaliectasis is usually detected by renal scintillation procedures, these findings support its use as a urinary tract screening examination along with an abdominal radiograph to detect calculi. The need for long-term serial examination of the urinary tract in spinal cord injury is emphasised.

Dilatation, Pathologic↗

PubMed1985

Measurement of glomerular filtration rate using 99mTc-DTPA and the gamma camera: a comparison of methods.

A variety of methods have been proposed to estimate the glomerular filtration rate (GFR) from the renal uptake of technetium Tc 99m-DTPA using a gamma camera. To compare alternative methods, we calculated the GFR in several different ways from measurements in 33 patients and compared the results with an independent GFR measurement based on eight-point plasma clearance of ytterbium Yb 169-DTPA. The best agreement was obtained using an algorithm that has not been described previously, in which correction was made for overlap of the kidneys by the liver and spleen. The correlation coefficient was 0.958, and the residual standard deviation was 12.1 ml/min. This method required a single 20-min blood sample as well as the camera data. The best method not requiring a blood sample was significantly less accurate, with a correlation coefficient of 0.837 and a residual standard deviation of 23.1 ml/min. The accuracy of these methods was comparable to that reported for creatinine clearance, the most commonly used estimate of the GFR in current clinical practice.

Glomerular Filtration Rate↗

PubMed1985

Free full thickness (patch) graft urethroplasty: long-term follow-up.

Thirty-two patients underwent free, full thickness skin (patch) graft urethroplasties between September, 1974, and May, 1978. Sixty-five per cent of the 23 patients available for five-year follow-up had good results from grafts ranging from 3 to 14 cm in length. In patients with good one-year results strictures did not develop during the review period, suggesting the need for only short-term follow-up in this group.

Adolescent↗

PubMed1985

Long-term followup of renal function after spinal cord injury.

Effective renal plasma flow was measured in acute spinal cord injury patients for up to 10 years after injury to determine the extent of renal deterioration in these patients and to identify the factors associated with a loss of renal function. The over-all mean decrease in effective renal plasma flow for all patients as a whole was 4.5 ml. per year. Factors associated with a statistically significant reduction in effective renal plasma flow included age, gender, renal calculi, quadriplegia, and a history of chills and fever. Other factors examined but not found to be statistically significant included years since injury, presence of severe decubiti, bladder calculi, bacteriuria and extent of injury. This study suggests that renal function usually can be preserved in spinal cord injury patients if the treatable risk factors are managed properly.

Adult↗

PubMed1985

Prophylactic antibacterial therapy for preventing urinary tract infections in spinal cord injury patients.

We conducted 202 trials in 161 male hospital patients to determine if prophylactic administration of ascorbic acid or antibacterials (trimethoprim-sulfamethoxazole, nalidixic acid, methenamine hippurate or nitrofurantoin macrocrystals) would prevent bacteriuria infections in spinal cord injury patients who had had at least 1 bout of bacteriuria. None of the drugs tested appeared to be statistically effective in the doses used in preventing bacteriuria in these patients. Moreover, sensitivities were lost to several drugs other than those used prophylactically. We conclude that use of prophylactic doses of ascorbic acid or antibacterials has not proved to be beneficial in spinal cord injury patients free of indwelling catheters.

Anti-Infective Agents, Urinary↗

PubMed1985

Effective renal plasma flow: clinical significance after spinal cord injury.

We conducted a study to determine if effective renal plasma flow routinely measured by hippurate clearance during a comprehensive renal scintillation procedure is a relevant measure for assessing renal function in spinal cord injury patients. All subjects had spinal cord injury and had had contemporaneous comprehensive renal scintillation procedures and excretory urograms on 2 occasions 24 months or less apart. Each of the 469 kidneys was placed into 1 of 5 quintiles on the basis of its effective renal plasma flow at the first examination. The percentage of the kidneys that had clinically significant pyelocaliectasis or in which the pyelocaliectasis significantly worsened was 20.4 per cent in the lowest (first) quintile and 9.3, 2.2, 5.4 and 3.2 per cent in the second, third, fourth and fifth quintiles, respectively. Analogous data for ureterectasis were 16.1, 8.2, 2.2, 3.3 and 3.2 per cent. There was a significant (p less than 0.01) correlation between effective renal plasma flow and renal parenchymal thickness. Kidneys with renal calculi averaged effective renal plasma flows about 25 per cent lower than those of kidneys free of calculi. We conclude that effective renal plasma flow is a relevant measure for assessing renal function in spinal cord injury patients.

Acute Disease↗

PubMed1985

Microsurgical vasovasostomy for reversal of elective bilateral segmental vasectomy.

Microsurgical vasovasostomy for the reversal of elective bilateral segmental vasectomy (vasectomy, vas ligation) was done in 57 patients (61 operations) between May 1977 and March 1984. The length of time between elective segmental vasectomy and subsequent vasovasostomy ranged from 12 to 216 months; the longest period between vasectomy and vasovasostomy resulting in a subsequent pregnancy was 108 months. The patency rate was 83%, with 51% of these patients fathering one or more children (overall pregnancy rate of 41%). Unlike previous studies, ours showed no positive correlation between the presence of postvasectomy sperm granulomas and either patency or pregnancy rate after microsurgical vasovasostomy. The major factor that seemed to affect the success of the procedure was the number of years between vas ligation and vasovasostomy.

Adult↗

PubMed1985

Measurement of glomerular filtration rate: single injection plasma clearance method without urine collection.

Glomerular filtration rate (GFR) can be calculated from the plasma clearance of any of several radiopharmaceuticals that are excreted by glomerular filtration. Simplified methods have been proposed that require only one or two plasma samples in lieu of a more complete clearance curve. We examined the error introduced by this simplification. Forty patients were studied using a dual-isotope technique employing [99mTc]DTPA and [169Yb]DTPA, obtaining eight plasma samples for each clearance curve at intervals from 10 to 240 min after injection. Data were fit to several empirical or semiempirical formulae and also to a two-compartment computer model that permitted GFR estimation from only one or two data points. The computer model gave good fit, but so did several simpler methods. The error that results from replacing the complete clearance curve by a single 3-hr sample was about 8 ml/min (residual s.d.). By using two samples (at 1 and 3 hr), the error could be reduced to 4 ml/min. Recommended one- and two-sample methods are presented.

Glomerular Filtration Rate↗

PubMed1984

Effect of skeletal muscle relaxants on bladder smooth muscle.

The present study was conducted to determine the effects of skeletal muscle relaxants on contractions of bladder smooth muscle. Rat, rabbit and human bladder muscle strips were incubated in a 50 ml. organ bath filled with physiological salt solution, aerated with 95 per cent O2, 5 per cent CO2 and maintained at 37C. Contractions were induced both electrically and with acetylcholine. Contractile strength was measured before and after 30 to 70 minute incubations with diazepam (0.25 to 1.0 microgram./ml.), dantrolene sodium (4 micrograms./ml.) or baclofen (4 micrograms./ml.). Neither baclofen nor dantrolene sodium had any effect (p greater than 0.3) on electrically or acetylcholine-induced contractions in any of the 3 species tested but diazepam potentiated both electrically induced (115 per cent of predrug contractile strength, p less than 0.05) and acetylcholine-induced (122 per cent of predrug contractile strength, p less than 0.01) contractions of rat, but not rabbit or human, bladder muscle. In rabbits diazepam significantly reduced maximal bladder pressures in vivo (p less than 0.05) but had no effect on bladder capacity. Dantrolene sodium had no effect on rabbit bladder pressure or capacity in vivo. While diazepam is thought to exert its effects on skeletal muscle through CNS inhibition, these results suggest that diazepam may affect rat but not rabbit or human bladder smooth muscle directly.

Acetylcholine↗

PubMed1984

Renal function after acute and chronic spinal cord injury.

Computer-assisted renal scintigraphy was performed on 160 acute and 240 chronic spinal cord injury patients, and 287 noninjured controls. Concurrently, measurements of global and individual kidney effective renal plasma flow, time of maximum activity in each kidney, ratio of maximum counts to the counts at 27 minutes after injection over each kidney and number of counts in each kidney at 1 to 2 minutes after injection were made. The time of peak activity over the kidney and differential function at 1 to 2 minutes after injection were not affected significantly by age, sex or spinal cord status. Global and individual effective renal plasma flows were significantly affected by all of these factors. Both plasma flow measures generally were higher for male than for female patients. Effective renal plasma flow decreased steadily after early adulthood and, except for the youngest and oldest patients, values were lower for spinal cord injury patients than for normal controls. The ratio of peak to 27-minute counts was affected significantly by age and spinal cord injury but not by sex. In patients without obvious pathological conditions followup scintigrams 1 to 3 years after injury showed no significant changes owing to interval since injury on any parameter studied. Lower limits of basal scintigraphic parameters are given for evaluation of renal status in neurologically intact or spinal cord injury persons.

Adolescent↗

PubMed1984

Serum creatinine as an indicator of renal function after spinal cord injury.

This study was conducted to determine (1) if serum creatinine levels (SCL) in spinal cord injury (SCI) patients are influenced by neurologic level of lesion, sex, age, or time since injury, and (2) if SC values are a sensitive indicator of renal function (as reflected by renal plasma flow [RPF]) in these patients. The overall SC mean and SD were 0.9 +/- 0.2mg/dl (n = 141). There was no difference in SC values between patients with higher injuries (T-6 or above) and patients with lower injuries (T-7 or below), nor was there any difference between patients with lesions less than 3 months, 10-14, 22-26, 34-38, 46-50, or 58-62 months in duration. Age and gender each accounted for less than 5% of the variation in SC. There was no significant correlation between RPF and SC (unless the patient also had moderate or severe pyelocaliectasis) nor between change in serum RPF (from the previous examination, usually 12 months earlier) and change in SC, suggesting that SCL does not reflect the functional status of the kidney in these patients.

Adolescent↗

PubMed1983

Failure of antibody-coated bacteria and bladder washout tests to localize infection in spinal cord injury patients.

The validity of the antibody-coated bacteria test and Fairley washout procedure to determine whether urinary tract infections were of kidney or bladder origin in spinal cord injury patients was assessed by comparing test results with those obtained from culture of ureteral urine specimens. It was concluded that neither the presence of antibody-coated bacteria nor a positive bladder washout test can be considered as definitive evidence that bacteriuria is of renal origin in these patients.

Antibody-Coated Bacteria Test, Urinary↗

PubMed1983

Quality control of Tc-99m DTPA for measurement of glomerular filtration: concise communication.

When technetium-99m DTPA is used to measure glomerular filtration rate (GFR), the accuracy depends on the supplier of the radiopharmaceutical. The error in GFR is due to protein binding, as we have shown by direct measurement. In 19 patients, GFR measured with Tc-DTPA and corrected for protein binding agreed with that measured simultaneously using Yb-169 DTPA (correlation coefficient 0.991). Without correction, Tc-DTPA gave falsely low values in patients having good renal function, in whom unbound activity cleared rapidly while bound activity remained in the circulation. When Tc-DTPA is used to measure GFR, the in vivo protein binding should be measured and used to correct the data.

Animals↗

PubMed1981

Comprehensive renal scintillation procedures in spinal cord injury: comparison with excretory urography.

A 131iodine orthoiodohippurate comprehensive renal scintillation procedure was performed and compared to results of excretory urography in 200 spinal cord injury patients. No severe urographic abnormalities were undetected by the comprehensive renal scintillation procedure. Only 1.4 per cent of renal units had greater than minimal pyelocaliectasis or ureterectasis in the presence of a normal radionuclide examination. A relatively large number of abnormalities were detected on the renal scintillation procedure when the excretory urogram was normal. Serial followup will be required to determine the significance of these findings but present data suggest that a comprehensive renal scintillation procedure and a plain film of the kidneys, ureters and bladder may be used for screening upper urinary tract abnormalities in lieu of an excretory urogram. This is particularly advantageous for the spinal cord injury population, since there have been no toxic or allergic reactions reported, no bowel preparation or dehydration is required and there is relatively low radiation exposure.

Humans↗