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Biomedical subjects

J James

Publications and source records attributed to J James.

At least 145 records · Page 8Linked to original sources
PubMed1986

Starvation-induced microautophagic vacuoles in rat myocardial cells.

During prolonged starvation the heart atrophies and loses protein mass. Debate lingers over the basic mechanisms in the production of negative cardiac protein balance during starvation. The extent to which cardiac proteolysis takes place within the lysosomal vacuolar system is unknown. The present communication examines the starvation-induced changes within the lysosomal system of rat myocardial cells, as studied by means of conventional electron-microscopic techniques. Special attention has been paid to the occurrence of microautophagic vacuoles. It is concluded that during prolonged starvation microautophagic vacuoles appear in rat myocardial cells, suggesting the induction of a microautophagic pathway of lysosomal proteolysis.

Animals↗
PubMed1986

Vitamin D nutrition and vitamin D metabolism in the premature human neonate.

The effect of supplementation with daily doses of vitamin D2 (1000 IU or 3000 IU, 25-75 micrograms, 63-189 nmol) has been studied in 39 premature neonates, initial gestational age 25-32 weeks. The initial mean plasma 25-hydroxyvitamin D was 25.8 nmol/l (10.3 ng/ml) but in 12 infants, most of whom were born in the winter months, the level was less than 15 nmol/l (6 ng/ml), and in seven babies plasma 1,25-dihydroxyvitamin D was less than 48 pmol/l (20 pg/ml). These findings suggest a considerable degree of maternal vitamin D-deficiency. Maximum attained concentrations of 25-hydroxyvitamin D on treatment were 77.3 nmol/l (30.9 ng/ml), high dose and 86.8 nmol/l (34.7 ng/ml), low dose, the mean rate of increase was greatest during the first two weeks (2.2 nmol/l/d; 0.88 ng/ml/d) and declined over the next 4 weeks. Mean maximum concentrations of 1,25-dihydroxyvitamin D2 were 283 pmol/l, (121 pg/ml), high dose and 309 pmol/l (129 pg/ml), low dose. Apart from a minor contribution to the initial plasma 1,25-dihydroxyvitamin D concentration, no effect of gestational age could be discerned in any of the measured variables. The endogenous pool of 1,25-dihydroxyvitamin D3 decayed with a T 1/2 of 22.5 d, indicating that vitamin D supplementation of these infants was necessary to avoid vitamin D-deficiency.

Calcifediol↗
PubMed1986

Death of osteocytes. Electron microscopy after in vitro ischaemia.

Ischaemia kills osteocytes, but opinions differ as to how long they can survive. These differences are due to the varying methods of inducing ischaemia, and to the different criteria for diagnosing cell death. Using rabbit bone and a technique of in vitro ischaemia at 37 degrees C, we have shown by electron microscopy that, after up to two hours, the changes which occur are probably reversible; after four hours, the cells were irreversibly damaged. This difference could not be detected by light microscopy. After 24 hours of ischaemia, most lacunae were empty or contained only osteocyte debris. We conclude that osteocytes suffer irreversible damage after in vitro ischaemia of about two hours, which is much the same response as that of most other mammalian cells.

Animals↗
PubMed1986

The role of filtration in the provision of leukocyte poor red cells to multitransfused patients.

Five techniques for the preparation of leukocyte poor red cells were investigated to compare their efficiency in preventing febrile transfusion reactions with their cost of production, in order to establish a cost-effective transfusion programme for chronically anemic patients. Leukocyte depletion and preparation costs per unit for the products were:--microaggregate filtered red cells (MF): 25% leucocyte removal at a cost of $A2; buffy coat poor red cells (BCP): 70% at $A2; washed buffy coat poor red cells (WBCP): 88% at $A28; cotton wool filtered red cells (CWF): 93% at $A23; reconstituted frozen red cells (FC): 97% at $A80. The 5 products were transfused into 103 thalassemia patients with a documented history of febrile transfusion reactions. Reaction rates, expressed as a percentage of units transfused over a 12 mth period (MF 7%, BCP 0.3%, WBCP 0.1%, CWF 0.1%, FC 0.2%) correlated well with the degree of leukocyte depletion. The cost of CWF was reduced by a further 10% using the filter in line during the transfusion. Serum from these patients was screened for leukocyte and platelet antibodies using microlymphocytotoxic, granulocyte immunofluorescence and platelet immunofluorescence assays. There was no correlation between the antibodies present and the type of leukocyte poor product required by a patient to prevent a febrile reaction. A progressive regimen of transfusion (BCP to CWF to FC as the patient reacts) has now been adopted, with considerable cost saving.

Blood Platelets↗
PubMed1986

A visible DNA-protein stain: Feulgen-Pararosanilin(SO2) Light Green.

Feulgen-Pararosanilin(SO2) Light Green, a DNA-protein stain, is described that is suited both for visual analysis and quantitative cytochemical measurement. The stain has been applied on cervical cells and quantitative aspects have been studied on chicken erythrocyte and rat liver nuclei. In comparison to single staining, the Feulgen-Pararosanilin(SO2) DNA content of the nuclei remains unaltered after application of the combined staining. The Light Green protein content is reduced considerably, however, dependent on the degree of chromatin condensation in the nucleus.

Animals↗
PubMed1986

Improved health care delivery in an inner-city well-baby clinic run by general practitioners.

The delivery of health care has been improved in an inner-city well-baby clinic by staffing the clinic with members of a primary health care team and by offering a therapeutic service together with a preventive service. Over a three-year period attendance at the clinic has doubled and the uptake of immunization has increased. Of children registered with the practice supplying the health care team, 95% are up to date with diphtheria, tetanus and polio immunizations and 93% have been immunized against measles. It is suggested that general practitioners should have greater involvement in the running of well-baby clinics.

Child, Preschool↗
PubMed1985

The effect of streptozotocin diabetes on insulin binding by isolated rat kidney tubules.

Preparations of kidney tubules were isolated from rat kidney cortex and were demonstrated to possess specific binding sites for insulin. The binding was time-and temperature-dependent and the label was displaced by bovine insulin, A1-B29 dodecoyl insulin, proinsulin and insulin A- and B-chains in proportion to their relative activity. Cell-associated degradation was studied by incubating tubules in the presence of fatty-acid-free albumin. The tubules showed high insulin-degrading activity, which was dependent on temperature, time and cell concentration. The number and affinity of insulin receptors on tubules isolated from kidneys taken from streptozotocin-diabetic rats was not significantly different from tubules isolated from untreated control or insulin-treated diabetic rats. Diabetes did not alter the kinetics of insulin degradation by the tubules. This lack of response by the tubules to changes in the concentration of circulating insulin supports the hypothesis that the kidneys do not play an active role in modulating the rate of insulin removal from the circulation.

Animals↗
PubMed1985

Pharmacokinetics and safety of ceftriaxone in the neonate.

The pharmacokinetics and safety of ceftriaxone were examined in 39 neonates who required antibiotics for clinically suspected sepsis. The drug was administered as a once daily dose of 50 mg/kg by the intravenous (IV) or intramuscular (IM) route. Ceftriaxone was assayed in 49 series of blood samples, 3 samples of cerebrospinal fluid (CSF) and 15 samples of urine by a microbiological technique. Blood was collected before, during and after treatment for biochemical analysis. Routine haematological investigations were also monitored. There was no significant difference between the maximum plasma concentrations following IV (153 +/- 39 mg/l) or IM (141 +/- 19 mg/l) administration (first dose). The mean elimination half-life, total body clearance, and volume of distribution following the first dose were 15.4 +/- 5.4 h, 0.28 +/- 0.12 ml/min per kg and 325 +/- 59 ml/kg respectively. Clearance increased with increasing postnatal age and body temperature (P less than 0.0002) and decreasing plasma creatinine concentration (P less than 0.005). Increasing plasma protein concentration was associated with a decrease in volume of distribution (P less than 0.001). There were no drug-associated changes in any of the biochemical or haematological parameters examined. Ceftriaxone is a safe and well tolerated antibiotic for use in the treatment of newborn sepsis and possibly meningitis. A once daily administration of 50 mg/kg by the IV and IM routes provides satisfactory plasma concentrations throughout the dosage interval whilst avoiding accumulation.

Bacterial Infections↗
PubMed1985

Cytochemical determination of acid phosphatase activity in isolated rat hepatocytes during starvation-induced proteolysis.

Acid phosphatase activity in isolated rat liver parenchymal cells has been investigated with quantitative histochemical means during short-term starvation, which leads to a considerable loss in protein mass in the parenchyma. Animals trained to a meal-feeding regime in which food was available during 1 h only per 24 h (using an automatic food dispensing machine), were sacrificed 6, 12, 18, 24 and 36 h after food had been withheld at the time point (23.00 h) of meal feeding. Acid phosphatase activity was analysed cytophotometrically in isolated hepatocytes incorporated into polyacrylamide gels before the enzyme reaction technique with the post-azo coupling was carried out. No indication could be found for any significant changes in the amount of acid phosphatase activity per individual hepatocyte during the entire period of fasting, as compared with two time points (11.00 and 23.00 h) before the theoretical onset of fasting. It is concluded that the considerable enhancement of protein degradation in the lysosomal apparatus during fasting is not reflected by changes in the cellular acid phosphatase activity.

Acid Phosphatase↗
PubMed1985

Quantitative analysis of mitochondrial flocculent densities in rat hepatocytes during normothermic and hypothermic ischemia in vitro.

The development of flocculent densities in mitochondria as a sign of irreversible cell injury in rat hepatocytes has been studied by quantitative electron microscopy during in vitro ischemia under both normothermic (37 degrees C) and hypothermic (4 degrees C) conditions. At 37 degrees C flocculent densities first appear after 1 h ischemia; at this stage they are small in diameter (170 nm) and occur in only 8% of mitochondria. After 1.5 hour ischemia, flocculent densities increase in diameter (207 nm) and are seen in 37% of mitochondria. Death of the majority of hepatocytes seems to occur between 1.5 and 2 h ischemia since at this stage the percentage of mitochondria containing flocculent densities reaches a maximum (48%). However, flocculent densities continue to increase in size (to 337 nm diam.) up to between 2 and 4 h ischemia (the prenecrotic phase). In contrast, at 4 degrees C signs of ischemic damage to hepatocytes are considerably delayed. Flocculent densities of comparable size and frequency to those observed after 1 h ischemia at 37 degrees C are not seen till as late as 4 days at 4 degrees C. At the latter temperature, only after 7 days ischemia a substantial rise (to about 25%) in the proportion of mitochondria containing flocculent densities occurs. A further slow increase in size and in the percentage of mitochondria containing densities occurs up to 14 days ischemia at 4 degrees C. It is concluded that the development of flocculent densities may be used only as a parameter of irreversible damage in cells with a sufficient number of mitochondria, such as hepatocytes, under normothermic conditions. With ischemia at 4 degrees C, possibly due to a different protein denaturation pattern, the development of flocculent densities is of much less value as an indication of irreversible cell damage and cannot, therefore, be considered as a reliable sign of cellular damage in organs stored at 4 degrees C for transplantation purposes.

Animals↗
PubMed1985

Ploidy class-dependent metabolic changes in rat hepatocytes after partial hepatectomy.

Glucose-6-phosphate dehydrogenase (G6PDH), succinate dehydrogenase (SDH) activity and the single-stranded RNA (ssRNA) content of isolated hepatocytes of different ploidy classes from adult male rats have been studied after partial hepatectomy using quantitative cytochemical means. The SDH activity and ssRNA content in all classes of hepatocytes are decreased during the first hours after operation followed by an increase above control values. The increase of both SDH activity and ssRNA content is significant only in the mononuclear diploid (MD) cells but not in the hepatocytes of higher ploidy classes and is related with the mitotic wave at 32 h after hepatectomy. After the mitotic wave, the values quickly return to normal levels. The G6PDH activity does not show any significant change in hepatocytes other than MD cells. In MD cells the G6PDH activity is elevated on a highly significant level up to a maximum value of 3.5 times the control value at 48 h after operation. The G6PDH activity in MD cells is returned to normal values within 14 days after operation. It is concluded that: 1. The MD cells show a distinct metabolic behaviour due to their function as stem cells of liver parenchyma and retain at least some of their fetal characteristics. 2. G6PDH activity is not a transformation-linked discriminant for neoplastic metabolism.

Animals↗
PubMed1985

Oro-facial granulomatosis: a possible allergic basis.

Food or flavouring intolerance has been demonstrated in 14 out of 80 patients with oro-facial granulomatosis. Provoking molecules include cinnamaldehyde, carvone and piperitone, although a wide range of food or flavourings may be implicated. The nature of the reaction is not understood but does not seem to involve an IgE mediated response. At present the only reliable way of detecting specific provoking factors is by the use of an elimination diet.

Allergens↗
PubMed1985

Ceftriaxone--clinical experience in the treatment of neonates.

A group of 104 neonates with clinical signs of infection sufficient to justify treatment with penicillin plus gentamicin received instead monotherapy with ceftriaxone (50 mg/kg once daily). Bacteriological cultures from 20 babies before treatment yielded significant isolates (9 had bacteraemia). Following treatment, infecting bacteria were eradicated from 15/20 babies. Ten of the 104 babies died; all were examined post mortem. Only one death was attributed to bacterial infection. The remaining babies responded well to treatment. No adverse alteration in biochemical or haematological values was associated with ceftriaxone therapy. The incidence of diarrhoea, blood in the stools, necrotising enterocolitis or anti-coagulation problems was the same as in the babies not receiving ceftriaxone. Pharmacokinetic values were determined on 40 babies. Elimination half life (T1/2 beta) and minimum serum concentration (Cmin.) decreased and clearance increased with increasing postnatal age. Postnatal age was the single most significant factor affecting pharmacokinetics. Ceftriaxone is a safe and effective alternative to conventional therapy for infected neonates. Prolonged therapy is associated with superficial colonisation with inherently resistant bacteria.

Bacterial Infections↗
PubMed1985

Influence of nutritional state on ischemic damage in rat liver.

The influence of the nutritional state of rats on the volume of necrosis in the liver at 24 h after 60 min ischemia has been estimated using fresh liver slices incubated in tetranitro BT. The volume of necrosis is about 30% in an animal fed ad libitum and about 10% in rats fasted for 24 h. Standardization of the time of feeding using a food dispensing apparatus did not reduce the relatively high individual variation in the extent of liver cell necrosis after ischemia. The beneficial effect of fasting on the extent of liver cell necrosis induced by ischemia may be due to decreased acidosis and/or a change in metabolic status.

Animals↗
PubMed1985

Experiences with standardized feeding of rats with an automatic food dispensing apparatus.

A simple automatic food dispensing machine can be used to train rats to a regime of meal-feeding during one hour at night. Apart from some 20% of the animals which fail to adapt but can be recognized early during training on the basis of weight curve, a population of animals is obtained which show a high degree of standardization of rhythmic changes related to food intake and apparently have an adequate supply of food as shown by the protein mass of liver cells.

Animal Nutritional Physiological Phenomena↗
PubMed1985

Urobehavioral intervention in the rehabilitation of lower urinary tract dysfunction: a case report.

A case study illustrates the usefulness of behavioral analysis and paradoxical strategy in the treatment of life-long urgency incontinence in a cerebral palsy patient. Volitional increase in diurnal enuresis appeared to result in rapid (within 5 days) acquisition of continence. From pretreatment to 13 month follow-up interview, the weekly wetting frequency decreased from an average of 25 to 0.5 episodes. Symptom rehearsal is believed to have interrupted the typical pathobehavioral sequence between the urge to void and micturition.

Adult↗
PubMed1984

The use of Light Green and Orange II as quantitative protein stains, and their combination with the Feulgen method for the simultaneous determination of protein and DNA.

The protein dyes Light Green and Orange II were studied separately and in combination with the Feulgen-Pararosanilin(SO2) and -Thionin(SO2) method for the simultaneous determination of DNA and protein. - With polyacrylamide modelfilms the pH dependency, specificity and stoichiometry of Light Green and Orange II have been investigated. The results of both staining methods with different biological objects have been compared. - In addition, the Feulgen-Thionin(SO2) method was studied with model films with respect to its specificity and stoichiometry. In biological objects it has been compared with the Feulgen-Pararosanilin(SO2) method. - When combining the Light Green staining with the Feulgen-Pararosanilin(SO2) procedure and the Orange II staining with Feulgen-Thionin(SO2), both Feulgen-DNA stainings, which were first applied, proved to be unaffected by the following protein staining procedure. When the Feulgen procedure was carried out without the dye, followed by Light Green staining, the latter became reduced when a sulfite water rinse was included but was unaffected when a running tap water rinse was used. In the case of the Orange II staining a serious reduction in dye binding capacity was found in both situations. - When the Feulgen-Pararosanilin(SO2) Light Green procedure was carried out on isolated nuclei with all dyes present, a decrease of protein dye binding was observed, similar to that found with the well-known Feulgen-Pararosanilin(SO2) Naphthol Yellow S combination. It is concluded that in spite of this reduction the latter two combinations can be used for the cytophotometric analysis of DNA and protein in the same object.

Animals↗