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Biomedical subjects

L John

Publications and source records attributed to L John.

At least 19 recordsLinked to original sources
PubMed1996

Peripheral blood pressure cells transplants across a major histocompatibility barrier in rabbits: positive effects of a higher number of precursor cells?

Peripheral blood precursor cells (PBPCs) are used with increasing frequency for hematopoietic transplants and have more or less replaced autologous bone marrow transplants. First clinical and experimental reports document the feasibility of PBPCs as a source for allogeneic transplants. Few data exist on the optimal procedure and the ideal number of cells for the transplant. We have previously shown in rabbits that PBPCs can be used for transplants even across a major histocompatibility barrier. We used this model to test whether the number of transplanted precursor cells would influence graft outcome. Adult outbred Red Burgundy rabbits were used as donors, New Zealand White rabbits of the opposite sex as recipients. One individual donor was taken for one individual recipient. Conditioning consisted of single-dose total body irradiation of 10 Gy followed by a short course of cyclosporine to enhance engraftment. Donor animals were treated with recombinant human granulocyte-colony-stimulating factor, 10 micrograms/kg subcutaneously daily from day -2 until day +9. PBPCs were obtained from the artery of the donor animal by repetitive centrifugation of 2 x 40 ml heparinized blood on each day of donation, i.e. days 0, +2, +3, +6, +8, and +10 and infused without further manipulation. Eight animals underwent transplantation. Seven took the grafts, six died of graft-versus-host disease and pneumonia between days 12 and 55 (median survival of all animals: 34 days). One animal was still alive after 120 days. Transplanted nucleated cells varied from 7.3 to 15.4 x 10(8)/ kg (median 9.2 x 10(8)/kg) and CFU-GM from 12.3 to 176.8 x 10(4)/kg (median 42 x 10(4)/kg). Survival tended to increase with more CFU-GM) r = 0.716, p = 0.0704). These data confirm that allogeneic PBPCs can engraft across a major histocompatibility barrier and suggest that a higher number of CFU-GM might be advantageous.

Animals↗
PubMed1996

Allogeneic peripheral blood precursor cell transplants in rabbits.

This report summarizes a series of experiments undertaken to evaluate the role of mobilized peripheral blood precursor cells (PBPC) for transplantation across a major histocompatibility barrier. Adult outbred red Burgundy rabbits were used as donors, New Zealand white rabbits of the opposite sex as recipients. Conditioning consisted of single dose total body irradiation (TBI) of 10 Gy supported by a short course of cyclosporine to enhance engraftment. Human recombinant G-CSF at a dose of 10 micrograms/kg was used for mobilization of precursor cells. Three methods of PBPC transplants were tested initially in 5 animals each. PBPC were collected and infused at once on day 0; collected initially, cryopreserved for one month, infused on day 0 and followed by 3 additional fresh donations or collected and infused on 6 occasions between days 0 and + 11. 13 animals engrafted, 2 became complete, longterm chimeras. Survival was best in the group given repetitive infusions (39 days median, 12 days to > 180 days, range). 10 additional animals were transplanted as in the last group and the number of transplanted nucleated cells (10.5 x 10(8)/kg median, 7.3 - 15.7 x 10(8)/kg range) and colony forming units CFU-GM (42 x 10(4)/kg median, 12.3 - 176.8 x 10(4)/kg range), were compared with outcome. Median survival of the 10 animals was 29 days (12 - 55 days range; 1 autologous reconstitution). Survival did not correlate with total nucleated cells per kg (r = 0.10; p = 0.79), but there was a trend to prolong survival with higher numbers of CFU-GM per kg (r = 0.47; p = 0.19). These data show that allogeneic PBPCT can engraft across a major histocompatibility barrier, that the high number of CFU-GM per kg might be advantageous, but also that additional methods are warranted to reduce acute GvHD.

Animals↗
PubMed1995

Transplantation of G-CSF mobilized allogeneic peripheral blood stem cells in rabbits.

Mobilized peripheral blood precursor cells (PBPC) are used with increasing frequency to restore autologous hematopoiesis following high-dose radio-chemotherapy. The success of this method has aroused interest in the use of mobilized PBPC for allogeneic transplants. This approach would eliminate the need for marrow aspiration and general anesthesia. In this project we tested the feasibility of allogeneic histoincompatible PBPC transplants in rabbits. Adult outbred Red Burgundy rabbits were used as donors, histoincompatible New Zealand White rabbits of the opposite sex as recipients. One individual donor was used for one individual recipient. Conditioning consisted of 10 Gy total body irradiation (TBI). Donor animals were pre-treated with recombinant human granulocyte colony-stimulating factor (rh G-CSF) given s.c. at 10 micrograms/kg daily. Three schedules of PBPC collection and reinfusion were tested in 3 groups of animals, each consisting of 5 donor recipient pairs: (A) PBPC were collected either on days -2, -1 and 0, and infused at once after TBI on day 0; (B) collected and infused on days 0, +2, +4, +7, +9, and +11; (C) collected on 3 consecutive days, cryopreserved for 1 month and infused on day 0 followed by 3 fresh donations on days +4, +8 and +11. The median amount of blood processed from donor animals was 470 ml (312-602) containing about 10 x 10(8) (5-71 x 10(8)) nucleated cells. Recipient animals received a median of 2.7 x 10(8) cells/kg equivalent to 9.6 x 10(4) colony-forming units granulocyte-macrophages (CFU-GM)/kg (data derived from Group C of the animals).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Respiratory depression following morphine and morphine-6-glucuronide in normal subjects.

1. Morphine 6-glucuronide (M6G) is a metabolite of morphine with analgesic activity. A double-blind, randomised comparison of the effects of morphine and M6G on respiratory function was carried out in 10 normal subjects after i.v. morphine (10 mg 70 kg-1) or M6G (1, 3.3 and 5 mg 70 kg-1). Analgesic potency was also assessed using an ischaemic pain test and other toxic effects were monitored. 2. Following morphine there was a significant increase in arterial PCO2, as measured by blood gases 45 min post dose (0.54 +/- 0.24 (s.d.) kPa, P < 0.001), and in transcutaneous PCO2 from 15 min post dose until the end of the study period (4 h), whereas blood gas and transcutaneous PCO2 were unchanged after M6G at 1.0, 3.3 and 5.0 mg 70 kg-1. This increased PCO2 following morphine was associated with an increase in expired CO2 concentration (FECO2) (0.20 +/- 0.14% expired air at 15 min post dose, P = 0.002), compared with small but significant reductions in FECO2 following morphine 6-glucuronide (-0.15 +/- 0.17% at 1 mg 70 kg-1 P = 0.030, -0.14 +/- 0.15% at 3.3 mg 70 kg-1 P = 0.017, -0.18 +/- 0.11% at 5 mg 70 kg-1 P = 0.024). Maximum transcutaneous PCO2 was significantly increased after morphine (0.63 +/- 0.28 kPa P = 0.009), but was not changed after M6G at 1 mg (0.10 +/- 0.34 kPa P = 0.11) 3.3 mg (0.06 +/- 0.37 kPa P = 0.34) or 5 mg (0.26 +/- 0.07 kPa P = 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Glomerular filtration rate in Indian non-insulin-dependent diabetics at various stages of albuminuria.

Sixty-seven non-insulin-dependent diabetic subjects were selected to estimate the glomerular filtration rate (GFR). All patients had satisfactory glycaemic control (HbA1 < 9.5%). GFR was determined using Technetium 99m DTPA by the method devised by Gates. Thirty-eight subjects had normal albumin excretion (UAE < 20 micrograms/min), 15 had UAE in the microalbuminuric range (20-100 micrograms/min), and the rest were macroalbuminuric (> 200 micrograms/min). GFR was lower in the normoalbuminuric patients as compared to the controls, but the decrease was not significant (71.5 (21.4) vs. 98.3 (16.1) ml/min per 1.73 m2. GFR was significantly decreased in both micro and macroalbuminuric groups (64.0 (24.5) and 53.8 (27.3) ml/min per 1.73 m2, respectively) (P < 0.05). No appreciable change in GFR was observed in normoalbuminuric patients with increasing duration of diabetes, however, there was a steady decline in GFR with time in both micro- and macroalbuminuric patients. Hypertension was present in 79%, 47% and 16% of macro-, micro- and normoalbuminuric patients, respectively. GFR was significantly lower in hypertensive diabetic patients compared to normotensives (52.3 vs. 76.1 ml/min per 1.73 m2) (P < 0.01), while this difference was not significant in the micro- and macroalbuminuric groups. We conclude from our study that the stage of hyperfiltration could not be detected in non-insulin-dependent diabetes and that hypertension has a significant influence on the rate of decline of GFR.

Adult↗
PubMed1994

Rate of progression of albuminuria in type II diabetes. Five-year prospective study from south India.

OBJECTIVE: To evaluate the potential risk factors for the progression of albuminuria in type II diabetes. RESEARCH DESIGN AND METHODS: A cohort of 481 type II diabetic patients were followed prospectively for 5 years. Blood glucose (BG) and blood pressure (BP) were checked at 2 monthly intervals, and urinary albumin excretion (UAE) was checked at yearly intervals. Progression of albuminuria was recognized by the development of microalbuminuria and macroalbuminuria and a significant increase in albuminuria within the microalbuminuric range. RESULTS: UAE was normal in 349 patients, 93 patients were microalbuminuric, and the rest (39) were macroalbuminuric. Sixty-two patients with normal UAE developed microalbuminuria. Ten patients with normoalbuminuria and 23 with microalbuminuria developed macroalbuminuria during the 5-year observation period with overall incidence of 46.9/1,000 person-years for normoalbuminuria and 58.7/1,000 person-years for microalbuminuria. Baseline UAE was significantly higher in those patients who progressed compared with those patients who did not (normoalbuminuria: 8.5 +/- 6 vs. 5.3 +/- 4 micrograms/min, P < 0.001; microalbuminuria: 68.5 +/- 57 vs. 47.4 +/- 34 micrograms/min, P < 0.01). Multiple regression analysis revealed initial UAE and diabetes duration to be predictors of albuminuria progression. CONCLUSIONS: Initial UAE is a strong predictor of albuminuria progression in type II diabetic patients.

Albuminuria↗
PubMed1993

Comparison of cardiovascular risk factors in type II (non-insulin dependent) diabetics with and without coronary heart disease.

Cardiovascular risk factors in NIDDM were studied by comparing 175 subjects with coronary heart disease (CHD) to 173 subjects without CHD; both groups were matched with regard to male to female ratio, age at diagnosis of diabetes and body mass index. The risk factors included were hypertension, poor metabolic control, smoking and lipid abnormalities. Since the mean known duration of diabetes in subjects with CHD was longer compared to those without CHD (12.93 +/- 7.23 and 6.25 +/- 5.66) and sub sample of subjects from both groups with duration of diabetes with 15 years or less were also analysed for comparison. Even after adjustment of duration the clustering of vascular complication in the subjects with CHD was striking. Presence of low HDL cholesterol was significant in both men and women diabetics with CHD (p < 0.01); while hypertension and poor metabolic control showed a strong positive correlation to CHD in women (p < 0.01 & p < 0.05). Multiple logistic analysis carried out separately in men and women showed that both low HDL cholesterol and elevated serum triglycerides showed strong association to CHD in both sexes; while in women in addition hypertension and insulin therapy also had a positive correlation to CHD (p < 0.01). Furthermore the influence of known duration of diabetes was not observed to be a significant contributor to the cardiovascular risk factors, since the above mentioned risk factors remained statistically significant in the subsample of patients with duration of diabetes less than 15 years.

Blood Glucose↗
PubMed1992

Induction of a cell-transferable suppression of alloreactivity by photodamaged lymphocytes.

We have reported previously that splenocytes from BALB/c mice acutely rejecting CBA/j skin allografts were exposed to 8-methoxypsoralen (8-MOP) and ultraviolet A light and infused several times intravenously into naive BALB/c recipients; the recipients were hyporesponsive to CBA/j alloantigens in skin graft and delayed-type hypersensitivity assays, as well as in mixed leukocyte culture and cytotoxicity assays. We currently expand on this work by showing that donor-specific tolerance can be transferred adoptively to naive syngeneic animals via unfractionated splenocytes from mice rendered tolerant by the previous protocol. This suppressed response to alloantigen was transferred optimally with splenocytes taken from mice on the sixth day after the final treatment with PET cells. We further demonstrate that the cells that are adoptively transferring suppression are radiosensitive, Thy-1+, Lyt-2+, L3T4- T lymphocytes.

Animals↗
PubMed1992

DNA associated with the cell membrane is involved in the inhibition of the skin rejection response induced by infusions of photodamaged alloreactive cells that mediate rejection of skin allograft.

Cell membrane DNA (cmDNA) is a form of DNA located on the surface of human and murine T-cells. It has recently been characterized as a target for photomodification by 8-methoxypsoralen (8-MOP) and long-wave ultraviolet light (UV-A). Whereas 8-MOP itself is biologically inert, photoactivated 8-MOP is covalently bound to pyrimidine bases in DNA. We have investigated the possible involvement of cmDNA photomodification in the induction of the suppression of skin allograft rejection in BALB/c mice preimmunized with 8-MOP/UV-A photodamaged alloreactive cells which mediates this allograft rejection. This suppression is demonstrated by inhibition of delayed-type hypersensitivity (DTH) and mixed leukocyte culture (MLC) responses. Splenocytes from BALB/c mice undergoing rejection of CBA/j skin graft which contained an expanded population of the effector T lymphocytes that mediate the rejection were treated with DNAse to remove cmDNA before or after treatment with 8-MOP and UV-A prior to infusion into naive BALB/c recipients. Mice that received pretreated effector cells were tested for MLC responses to CBA/j or B10 alloantigens before and after the DTH response. The DTH response of all groups of pretreated BALB/c mice to the relevant alloantigen was specifically suppressed as compared with the response of control mice. However, adoptive transfer of the suppression of the DTH response was optimally demonstrable only in syngeneic recipients of cells from donor mice treated with photodamaged alloreactive cells. Also, splenocytes from BALB/c mice immunized with photodamaged alloreactive cells demonstrated highly significant hyporesponsiveness and suppression of the MLC response of naive mice to the relevant alloantigen in the case of the primary MLC response, and to both alloantigens in the secondary MLC response which was totally eliminated by prior pretreatment of these effector cells with DNAse. Therefore, it appears that the suppression of the DTH response can be induced by pretreatment of the effector cells with DNAse and/or 8-MOP and UV-A but is adoptively transferable optimally only from mice which are recipients of photodamaged alloreactive cells. Moreover, the effectiveness of this treatment is decreased by prior removal of cmDNA from these cells. The presence of cmDNA is necessary for induction of suppression of the primary and secondary MLC responses in mice treated with photodamaged cells of allograft rejection.

Animals↗
PubMed1992

Betamethasone in tetanus patients: an evaluation of its effect on the mortality and morbidity.

The effect of betamethasone on the outcome in moderate to severe tetanus was studied in a randomised, double blind, placebo controlled study in 22 patients. The mortality rate was reduced by 36.1% with the addition of corticosteroids to the regime of treatment. Betamethasone did not alter the duration of intensive care in those requiring it, but reduced the need for tracheostomy and ventilation. The mean daily dose of diazepam required was not significantly different between the two groups and there was no increase in the incidence of infections in the betamethasone group.

Adult↗
PubMed1991

Inhibition of antiskin allograft immunity induced by infusions with photoinactivated effector T lymphocytes (PET cells). Is in vivo cell transferrable?

We previously reported producing donor-specific tolerance to alloantigens by intravenous exposure to pretreated antidonor T cells. The current study extends that work by adoptively transferring the donor-specific tolerance into naive syngeneic recipients. Eight days after BALB/c mice received histoincompatible CBA/j skin grafts, their splenocytes which included an expanded population of cells mediating rejection were treated with 100 ng/ml 8-methoxypsoralen (8-MOP) photoactivated by 1 Joule/cm2 of ultraviolet A (UVA) light prior to infusion into naive BALB/c recipients. Whereas 8-MOP itself is biologically inert, photoactivated 8-MOP crosslinks DNA by covalently binding to pyrimidine bases. Recipient BALB/c mice which had been previously demonstrated to be hyporesponsive to CBA/j alloantigens in mixed leukocyte culture (MLC), cytotoxicity (CTL) and in vivo delayed type hypersensitivity (DTH) assays were the donors of spleen cells for the adoptive transfer experiments. Fifty to one hundred million viable spleen cells from these pretreated BALB/c mice were transferred into naive syngeneic recipients which then were tested for DTH response and allograft survival to the relevant and irrelevant antigens. The radiosensitivity of this transferrable suppression was evaluated by exposing the adoptively transferred cell population to 3200 rads of C-irradiation prior to cell transfer. The phenotype of the cells transferring this suppressive response was performed by depleting specific populations of cells with monoclonal antibodies prior to cell transfer. In vivo the DTH response of the pretreated BALB/c mice was specifically suppressed to the relevant alloantigen, correlating with retention of CBA/j skin grafts for up to 42 days post engraftment without visual evidence of rejection, in comparison to control mice complete rejection of the skin graft in less than 8 days. In vitro, splenocytes from BALB/c recipients of pretreated syngeneic splenocytes containing large numbers of BALB/c anti-CBA/j T cells proliferated less in MLC and generated lower cytotoxic T cell responses to CBA/j alloantigens than did controls and suppressed the naive and sensitized BALB/c MLC and CTL responses to CBA/j alloantigen. This specific suppressive response to alloantigen was optimally transferred into syngeneic naive recipients when the adoptive transfer was performed on the sixth day after the last infusion received by the spleen cell donor mice. The adoptive transfer of this suppressive response was abrogated by the prior X-irradiation of the donor spleen cells and significantly abolished by the depletion of Thy-1+, Lyt-2+, L3T4- T lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Complement activation during bypass in acquired C1 esterase inhibitor deficiency.

Serial complement estimations during cardiopulmonary bypass are reported in a patient with acquired C1 esterase inhibitor deficiency. Although the extent of classic and alternative pathway activation appeared appropriate, exaggerated common pathway activation with massive increase in the C3d:C3 ratio occurred. A fatal hemostatic disorder, pulmonary edema, and circulatory collapse ensued despite prophylaxis and therapy.

Aged↗
PubMed1991

Inhibition of anti-skin allograft immunity induced by infusions with photoinactivated effector T lymphocytes--the congenic model.

We have previously reported the capacity to produce donor-specific tolerance to alloantigens by intravenous exposure to pretreated antidonor T cells. The current study has refined this system by using congenic mice differing only at the H-2 major histocompatibility complex genetic loci. Twelve days after B10 mice received MHC-incompatible B10.D2 skin grafts, their splenocytes that included an expanded population of cells mediating rejection were treated with 100 ng/ml 8-methoxypsoralen (8-MOP) photoactivated by 1 J/cm2 of ultraviolet A prior to infusion into naive B10 recipients. Whereas 8-MOP itself is biologically inert, photoactivated 8-MOP crosslinks DNA by covalently binding to pyrimidine bases. Recipient B10 mice were tested for tolerance to B10.D2 alloantigens in mixed leukocyte culture (MLC), cytotoxicity (CTL), and to in vivo delayed type hypersensitivity assays and challenged with a fresh B10.D2 graft. In vivo, the DTH response of the pretreated B10 mice was specifically suppressed to the relevant alloantigen, correlating with retention of B10.D2 skin grafts for up to 22 days postengraftment without visual evidence of rejection, in comparison to control complete rejection of the skin graft in less than 12 days. In vitro, splenocytes from B10 recipients of pretreated syngeneic splenocytes containing large numbers of B10 anti-B10.D2 T cells proliferated less in MLC and generated lower cytotoxic T cell responses to B10.D2 alloantigens than did controls and suppressed the B10 MLC and CTL responses to B10.D2 alloantigen. These results reveal that, in a highly defined congenic transplantation system, infusions of photoinactivated effector cells resulted in selective inhibition of the in vivo responses that correlated with allograft rejection and permitted prolonged retention of histoincompatible skin grafts. This approach may have significant practical applicability for treatment of human disorders caused by aberrant T cells.

Animals↗
PubMed1991

Hematologic values of New Zealand white rabbits determined by automated flow cytometry.

Hematologic values of peripheral blood from normal adult New Zealand White rabbits were determined by five different automated flow cytometers in use in a routine clinical hematology laboratory: Technicon H1, Coulter Counter CC540, Coulter Counter VCS, Sysmex NE8000 and Sysmex R1000. The software designed for human blood analysis was used in all instances without adaptation. The total numbers of white blood cells, red blood cells, reticulocytes and platelets were measured with high precision and accuracy. Except for hemoglobin content, concordance was excellent for all measured and calculated values among the different automated flow cytometers. Determining the white blood cell differential count was more complex. Eosinophils and lymphocytes were quantified reliably by all the automated flow cytometers used. However, the results were rejected by Technicon H1 and Sysmex NE8000 in 50% of the cases. Rabbit basophils were recognized with accuracy by Technicon H1 only. The proportion of polymorphonuclear versus mononuclear white cells was identical when measured with Technicon H1 and Coulter Counter VCS. These results show that the new generation of automated flow cytometers designed for human blood can be used with some limitations for animal studies. They allow the standardization of normal values and comparison of results among or between laboratories. They also introduce new parameters, the value of which is as yet undefined.

Animals↗