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Biomedical subjects

S R Jones

Publications and source records attributed to S R Jones.

At least 109 records · Page 6Linked to original sources
PubMed1991

Culture characteristics of Trypanosoma catostomi and Trypanosoma phaleri from North American freshwater fishes.

Culture characteristics of two species of piscine trypanosomes were compared. Trypanosoma catostomi from Catostomus commersoni was isolated in hypo-osmotic blood agar media but not in hyper-osmotic media. However, T. phaleri from Amia calva was isolated in both media. Only T. catostomi was stimulated to divide by diluting infected blood with water. The maximum number of T. phaleri and percentage of trypomastigotes were not affected by NaCl concentration. The maximum number of T. catostomi was inversely related to osmotic pressure and the percentage of trypomastigotes was directly related to osmotic pressure. This was confirmed by using equi-osmotic concentrations of NaCl, NaBr, Na acetate, KCl, choline-Cl or sucrose. Supplementation with urea had no effect on the number or morphology of trypanosomes. The survival of T. catostomi following cryopreservation was enhanced by prior incubation in hyper-osmotic media. Differential culture characteristics of these species may reflect adaptation to different host-vector systems.

Animals↗
PubMed1991

Assessment of a screening process to detect patients aged 60 years and over at high risk of hypothyroidism.

General practitioners are increasingly expected to screen elderly patients for common disorders, such as hypothyroidism, and the identification of at-risk patients by simple means would reduce the financial and other costs of such screening. A general practice based study of 1193 patients aged 60 years and over has been carried out to investigate the usefulness of the following factors in identifying those in whom biochemical testing for hypothyroidism would be indicated: personal history or family history of thyroid disease, symptoms of thyroid disease and body mass index. Of the 190 patients with either a personal or family history of thyroid disease, 28 (14.7%) had an elevated concentration of thyroid-stimulating hormone. Thus, 66 of the 94 patients (70.2%) with elevated concentrations of thyroid-stimulating hormone had no such thyroid history. Similarly, only nine (4.7%) of the patients with a personal or family history of thyroid disease required thyroxine replacement therapy. Thus, 22 of the 31 patients (71.0%) requiring such treatment had no such history. Discriminant analysis of the responses of women patients to questions concerning personal or family history of thyroid disease, the presence of symptoms of hypothyroidism, their age and body mass index identified only 51.3% of those with an elevated thyroid-stimulating hormone concentration and 77.2% of those with normal thyroid-stimulating hormone. Analysis of the responses of the men patients was even less discriminating.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Infections in frail and vulnerable elderly patients.

Frail and vulnerable elderly patients, recognized primarily by the presence of such disabilities as immobility, incontinence, and dementia, are at particularly high risk for the development of infectious diseases, which are the leading cause of hospitalization in this population. The infectious diseases most often observed in the debilitated elderly are pneumonias, urinary tract infections, skin infections, and gastroenteritis, with fever a common manifestation. Some of the factors identified as contributing to their increased susceptibility include diminishing physiologic functioning; compromised host-defense mechanisms; increased incidence of mechanical risk factors, such as pressure ulcers, indwelling or condom catheters, feeding tubes, and soft tissue injuries; and comorbidities such as soft tissue or pulmonary edema. In addition to the common infecting pathogens found in the general population, these unique compromising factors increase the risk of elderly patients for aerobic gram-negative bacillary infection. Further increasing the therapeutic dilemma are ethical considerations involved in prolonging treatment that might be considered medical intervention beyond what is routine and necessary. Although the decision to treat must be made on an individual basis, studies have not always shown treatment to provide benefits in terms of quality of life. Once it is decided to treat, however, appropriate therapy is crucial. One of the most important considerations is renal function, which impacts on effectiveness, toxicity, and cost of therapy and is likely to be diminished in elderly patients. A non-nephrotoxic agent, such as aztreonam, may be a more appropriate therapeutic choice than an aminoglycoside antibiotic in this patient population.

Aged↗
PubMed1990

Modification to a commercial immunoradiometric assay permitting intraoperative monitoring of parathyroid hormone levels.

We describe a modification to a commercially available immunoradiometric assay which reduces the turnaround time for parathyroid hormone (PTH) measurement to 1 h and permits intraoperative monitoring during parathyroidectomy. Alterations in PTH concentrations following removal of parathyroid tissue are compared with those of calcium, ionised calcium and phosphate. PTH measurements obtained intraoperatively permit definitive conclusions about the success of the operation within 1 h of sampling, allowing re-exploitation of the gland to take place immediately if necessary.

Calcium↗
PubMed1990

Cryptobia cataractae from the blood of Semotilus atromaculatus: structure and division in the fish.

A cryptobiid was found in the blood of 2 of 9 Semotilus atromaculatus from a tributary of the Saugeen River in Ontario, Canada. Blood inoculation produced an infection in 2 uninfected S. atromaculatus but not in any Oncorhynchus mykiss, Catostomus commersoni, or Carassius auratus. The flagellate was identified as Cryptobia cataractae, based on host restriction. Cryptobia cataractae occurred as slender and broad forms (body width 3.0-8.7 microns). The length of the anterior flagellum was equal to body length, whereas that of the free recurrent flagellum was half body length. Cryptobia cataractae divided by equal binary fission that produced elongate, slender daughter cells.

Animals↗
PubMed1989

Does post-tetanic potentiation compensate for low frequency fatigue?

The purpose of this study was to examine the effect of post-tetanic potentiation on low frequency fatigue in adult human quadriceps muscle. Sixteen subjects (10 male and six female) performed three 60 s sets of knee extension exercise in order to induce low frequency fatigue (reduction in torque output at 10 and 20 Hz). The potentiating stimulus (a 10 s maximal voluntary contraction) induced a 58% increase in twitch tension (Pt) during the pre-fatigue state. Immediately following the fatiguing exercise, torque (X +/- SE, Nm) at 10 and 20 Hz (submaximal transcutaneous stimulation, 50 microsecond pulses) decreased (P less than 0.05) from 54.8 +/- 5.8 and 94.9 +/- 9.6 to 40.3 +/- 6.1 and 77.0 +/- 11, respectively. Although potentiation at this time increased Pt from 40.9 +/- 4.0 to 54.8 +/- 3.7 (P less than 0.05), torque at 10 and 20 Hz was unaffected. At 60, 120 and 240 min post-contraction, torque at 10 and 20 Hz remained depressed. Following potentiation, which increased twitch tensions to between 64 and 75%, torque at 10 Hz was increased (P less than 0.05) at 60 min (36.3 +/- 4.1 vs. 50.7 +/- 6.2), 120 min (40.8 +/- 6.3 vs. 56.5 +/- 8.9) and 240 min (42.0 +/- 4.7 vs. 57.5 +/- 8.3) of recovery. Similar effects were also noted at 20 Hz. These findings indicate that post-tetanic potentiation can overcome the low frequency fatigue during the post-contraction period and restore torque to pre-exercise levels.

Adult↗
PubMed1989

Chronic salicylate intoxication. A common cause of morbidity in the elderly.

We reviewed the clinical profile of adults with chronic salicylate intoxication by evaluating the experience of our community teaching hospital between 1977 and 1987. Data on similar patients reported was obtained from an English-language literature search using MEDLINE (1966-88) and bibliographic reviews of textbooks and review articles. We also examined the impact of education and incentive on increasing the awareness and ability of physicians to diagnose the disorder. Chronic salicylate intoxication was defined by 1) a compatible clinical syndrome; 2) a serum level in the toxic range; and 3) improvement with withdrawal of the drug. Patients with chronic salicylism represent a cross-section of an elderly population. Our review suggests that diminished body mass, concurrent administration of drugs and conditions which exacerbate renal insufficiency may predispose to salicylate intoxication; however, few specific precipitants of chronic salicylism were recognized. Salicylate intoxication should be considered in all elderly patients with delirium and/or dementia.

Activities of Daily Living↗
PubMed1989

Use of kidney impressions for the detection of trypanosomes of anura.

The sensitivities of three techniques used for detecting infections of Trypanosoma spp. in frogs (Rana spp.) were compared. In total, 52 of 99 frogs had detectable infections of T. rotatorium, T. chattoni, T. pipientis or T. ranarum. Two or more Trypanosoma spp. were detected in 12 frogs. Microscopic examination of stained kidney impressions (KIT) was more sensitive than either hematocrit centrifugation (HCT) or wet-mount examination (WME) in detecting T. rotatorium and T. chattoni. The HCT was more sensitive in detecting T. pipientis and T. ranarum. Four infections of T. rotatorium that were missed using the HCT were detected using the WME; one of these was missed using the KIT. Success of the KIT may be related to size of the trypanosome while success of the HCT may be related to size, motility or specific gravity of the trypanosome.

Animals↗
PubMed1989

Performance and diagnostic application of a two-site immunoradiometric assay for parathyrin in serum.

The "N-tact" immunoradiometric assay (IRMA) from INCSTAR for parathyrin (PTH) in serum involves a 125I-labeled affinity-purified antiserum to PTH 1-34 and an affinity-purified antiserum to PTH 39-84, the latter bound to a polystyrene bead. The mean detection limit, determined in six consecutive assays, was 4 ng/L. The within-batch CV was less than 7% in the range 15 to 2135 ng/L. The between-batch CV was 11.7% and 5.3% at 30 and 371 ng/L, respectively. Serum PTH in 14 proven cases of primary hyperparathyroidism was 49-808 (median 111) ng/L, undetectable (less than 5 ng/L) in 10 cases of primary hypoparathyroidism and in 10 cases of hypercalcemia associated with malignancy, compared with 7-39 ng/L in 45 normal subjects. PTH was 9 to 19 ng/L in four patients with familial benign hypercalcemia. In 39 patients with renal failure, apparent concentrations were 14 to 857 (median 133) ng/L, but sera from these patients pre-diluted with zero standard did not parallel dilutions of the standard, PTH 1-84. PTH concentrations were not significantly decreased in blood or serum kept at 20 degrees C for up to 6 h. After successful removal of a parathyroid adenoma, the mean half-time for disappearance of PTH in vivo in five hyperparathyroid patients was 3.3 min.

Adult↗
PubMed1988

Gender difference in the relationship of performance in the handgrip and standing long jump tests to lean limb volume in young adults.

Groups of young, adult males and females performed the handgrip and standing long jump tests. Their total forearm and leg volumes were calculated from a series of circumference and length measurements, and the lean volumes (bone + muscle) calculated by taking the skinfold thickness into consideration. In the handgrip, the mean female performance was 298 N compared with 496 N for the males. In the standing long jump, mean performance expressed as distance x body mass was 87.3 kg.m for females compared with 137.7 kg.m for males. These superior performances of males could simply reflect their greater muscle mass, as the mean lean volumes of female and male limbs respectively were 0.54 l and 0.89 l for forearms, and 11.82 l and 14.82 l for the two legs. However, when the performances of males and females were grouped by lean limb volume, it was found that while in both tests there were linear relationships, males and females did not share a common line. In both tests the male relationship was at a higher level than the female; therefore, for a given lean volume, the male performance was significantly superior to that of the female. The gender difference found in this study has not been seen in other studies in which the performance of skeletal muscle has been related to the cross-sectional area of the active muscles and the possible reasons for the differences are considered.

Adolescent↗
PubMed1988

Amniotic fluid alpha-fetoprotein subfractions in fetal Trisomy 21 affected pregnancies.

The percentage contribution to the total AFP concentration in amniotic fluid from the yolk sac derived AFP was measured at 15-17 weeks gestation in 15 pregnancies affected by fetal Trisomy 21 and compared with that in 75 pregnancies with a normal outcome. The yolk sac form of AFP was reduced in parallel to the total AFP and differentiation of the subfraction from the yolk sac would offer no increase in diagnostic efficiency.

Adult↗