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Biomedical subjects

R Stock

Publications and source records attributed to R Stock.

At least 19 recordsLinked to original sources
PubMed1995

Induction of an autoimmune response against syngeneic lymphoma cells by immunogenic 64-kDa protein isolated from normal blast cells of BALB/c mice.

Immunogenic proteins with identical molecular mass (64 kDa) were purified from a syngeneic spontaneous T cell leukaemia line, designated LB3, and lymphoblast extracts both derived from BALB/c mice. The 64-kDa protein was purified by a sequence of biochemical steps from cell extracts containing protease inhibitors. The following steps were included in the purification pathway: Sephadex G-100 gel filtration, anion-exchange chromatography, concanavalin A (ConA) affinity chromatography, and preparative gel electrophoresis. The immunogenic fraction isolated in each step was subjected to the next step along the purification pathway. The immunogenicity of the separated fractions was measured by a lymph-node proliferation assay, which is indicative of delayed-type hypersensitivity. The final 64-kDa isolated protein of blast cells induced in BALB/c mice an efficient lymph-node proliferation response, which was detected in the regional lymph node after challenge with the final isolated protein of LB3 cells and vice versa. In addition to their identical molecular mass, both proteins were eluted from an anion-exchange column with the same NaCl concentration (0.57 M) and both expressed affinity to the ConA-Sepharose column, suggesting that they are glycosylated. The specificity of the immunological responses induced or elicited with the various isolated proteins was also shown. The implications of these findings are discussed.

Animals↗
PubMed1995

Age estimation in biopsy specimens of dentin.

Determination of age at death on the basis of aspartic acid racemization in dentin is one of the most reproducible and accurate methods. In Germany, age estimation by this method has so far generally not been applied to living persons, since the extraction of a tooth exclusively for age estimation when it is not medically indicated is regarded as ethically and legally problematic. The development of a biopsy technique applicable to dentin took place against this background. Testing the technique and analysis of dentinal biopsy specimens revealed that the biopsy technique is a low-risk procedure that causes only minor discomfort to the affected person. It is readily practicable and facilitates standardized specimen removal. The relationship between the extent of aspartic acid racemization in dentinal biopsy specimens and age is very close, facilitating age estimation. A prerequisite for accurate results is the performance of biopsies under strictly standardized conditions. If this is guaranteed, age determination on the basis of aspartic acid racemization in dentinal biopsy specimens appears to be superior in precision to most other methods in living persons and can be used for all age groups.

Adolescent↗
PubMed1995

Identification of glucan-mannoprotein complexes in the cell wall of Candida albicans using a monoclonal antibody that reacts with a (1,6)-beta-glucan epitope.

The use of a novel monoclonal antibody (mAb) that reacts with (1,6)-beta-glucan has permitted the study of the different covalent linkages between glucan and mannoproteins in the cell wall of Candida albicans. The mAb JRR1 was originally raised by immunization with Zymolyase extracts from C. albicans cell walls, but it soon became apparent that it reacted with a (1,6)-beta-glucan epitope. By using this antibody, we show the existence of glucan-mannoprotein complexes between the (1,6)-beta-glucan epitope recognized by the antibody and cell wall mannoproteins. The topology of the (1,6)-beta-glucan in the cell wall of C. albicans has also been studied.

Antibodies, Monoclonal↗
PubMed1995

Laparoscopic pelvic lymph node dissection combined with real-time interactive transrectal ultrasound guided transperineal radioactive seed implantation of the prostate.

Laparoscopic pelvic lymph node dissection with real-time interactive transrectal ultrasound guided transperineal radioactive seed implantation is a new method of treatment for localized carcinoma of the prostate. A total of 58 patients with clinically confined prostate cancer and negative seminal vesicle biopsies underwent staging laparoscopic pelvic lymph node dissection immediately followed by prostate implantation: 50 had 125iodine and 8 had 103palladium implants. Mean operating time was 226 minutes (range 120 to 475), mean blood loss was 57 cc (range 5 to 400) and average hospital stay was 2.2 days (range 0.5 to 8). At a mean followup of 12 months (range 6 to 24), complications included proctitis in 1.7% of the cases, dysuria in 24%, nocturia in 21% and outlet obstruction in 17%. Erectile function remained unchanged. Prostate volume decreased to 58.9% of the pretreatment value by 12 months and to 44.3% by 24 months. Mean prostate specific antigen level was 18.4 +/- 26.3 ng./ml. before treatment, 3.4 +/- 3.9 ng./ml. at 6 months, 2.3 +/- 2.3 ng./ml. at 12 months and 4.9 +/- 6.0 ng./ml. at 24 months (1.2 +/- 1.0 ng./ml. for patients with no evidence of disease). Of the patients 15.8% had local failure at 18 to 24 months as determined by positive transrectal ultrasound guided biopsy. Five of 58 patients (8.6%) had persistently elevated prostate specific antigen levels, only 1 of whom had a positive biopsy. Laparoscopic pelvic lymph node dissection with transrectal ultrasound guided implantation is a safe and promising mode of therapy for patients with localized prostate cancer.

Aged↗
PubMed1995

Computerized interactive morphometry in the differential diagnosis of irradiated prostates.

Radiation therapy is becoming a treatment of choice for many patients with prostatic carcinoma. Distinguishing radiation change in prostate glands from carcinoma may be difficult. In this study we objectively assessed, by morphometric methods, the nuclear characteristics of benign and malignant prostates with a history of radiation treatment (125I implant with or without prior external beam radiation). This is part of our continuing efforts to achieve difficult differential diagnoses by analyzing perimeter, diameter and nuclear profile area of cells or interest and applying methods of statistical classification. Biopsies were performed 18-36 months following implant therapy. Eleven cases with residual prostate tumor constituted the malignant group. These were compared to 20 benign cases (benign glands in the 11 carcinoma cases plus 9 other cases with no residual carcinoma). Immunohistochemical staining with keratin 903 was performed on all cases. Differences in the nuclear parameters were most evident in the average nuclear profile areas (32.5 microns 2 for the malignant groups vs. 39.6 for the benign) and in the mean maximal cord length (diameter) (7.4 microns for the malignant group vs. 9.0 for the benign). Classification, however, is based on the size distribution plots of nuclear profile areas, which, in the malignant cases, had a sharper peak at lower value, while the benign cases had higher value and a broader peak with a trailing off into the larger values. This study emphasized the marked nuclear alterations that occur in irradiated prostates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Intrauterine intravascular transfusion for fetal haemolytic anaemia: the Western Australian experience.

OBJECTIVE: To report the first four years' clinical experience with fetal intravascular blood transfusion for the treatment of fetal haemolytic anaemia in Western Australia. SETTING: King Edward Memorial Hospital, Perth, which is the sole tertiary level perinatal centre in Western Australia with a referral base of approximately 25,000 pregnancies each year. METHODS: Transfusion was by injection of packed cells from Rh-negative donors into the fetal umbilical vein near the site of insertion into the placenta. Fetal haemoglobin levels were measured before and after each transfusion. In most cases, the fetus was paralysed by intramuscular tubocurarine. RESULTS: Sixty intravenous transfusions were performed in 20 pregnancies. At the time of the initial transfusion, the mean haemoglobin level was 5.8 g/dL (range, 2.5-8.5 g/dL) and six fetuses had signs of hydrops. The case survival rate was 80% and the procedure survival rate was 93%. Three of the deaths occurred in the first five cases. Caesarean section was performed during two of the procedures, one because of bleeding from the cord puncture site and one because of tamponade of the umbilical vessels. CONCLUSION: Fetal intravascular transfusion is a highly effective treatment for fetal alloimmunisation and allows pregnancies to continue to term and to be delivered vaginally. However, the procedure may be difficult and requires a team approach with ready access to fetal monitoring and emergency caesarean section. Our results suggest that increasing experience of the team is a major factor in improved outcome.

Adult↗
PubMed1985

Health care for some: a Nigerian study of who gets what, where and why?

The persistent underdevelopment of health in the Third World belies the optimism of the "Health care for all by the year 2000" campaign. In order to understand the underdevelopment of health, it is essential to examine the historical evolution of specific health systems. These ideas are developed in a case study of health care in Kano State, Nigeria. The nature and contemporary development of the health care system, which includes state voluntary agency and private sector outlets for Western scientific medicine and a large and varied traditional medicine sector, are examined. Although the deepening health care crisis may potentially spur a reconsideration of priorities and strategies, past experience suggests that a stubborn retention of a pared-down and increasingly unjust version of the present system is more likely.

Health Resources↗
PubMed1983

Distance and the utilization of health facilities in rural Nigeria.

The distance patients must travel in order to obtain treatment has long been recognized as a primary determinant of the utilization of health care facilities. The distance factor is especially significant in rural Third World settings where the density of Western-type health facilities is often low, where the majority of patients are likely to make the journey for treatment as pedestrians and where there are viable and usually more accessible alternate sources of medicine. This study examines the impact of distance on the utilization of health care facilities in the Hadejia area of Kano State, Nigeria. Per capita utilization was found to decline exponentially with distance. The rate of distance decay in utilization levels varies according to the type of facility, socio-demographic variables and illness. Hausa perceptions about sickness and about specific illnesses are reflected in the varying incidence of health facility utilization in the treatment of particular illnesses and distance decay gradients of varying steepness. Although the per capita consumption of health care decreases exponentially for concentric distance bands, individual villages show great disparities in utilization rates which are only partly attributable to distance.

Adult↗
PubMed1983

Impact of weighing procedures and variation in protein degradation rate on measured performance of growing lambs and cattle.

A lamb growth trial was conducted to evaluate soybean meal and blood meal and to compare two experimental designs (a completely randomized design and a switchback design). A larger amount of variation was observed with the switchback than with the randomized design. A larger number of animals, longer treatment period or increased number of weighings may be needed to overcome end point weighing errors and decrease the variation in the switchback design. In both designs, there was a significantly greater conversion of protein to gain for blood meal (BM)-supplemented lambs than for soybean meal (SBM)-supplemented lambs. The relative value of BM compared with SBM was 251% (completely randomized design) or 296% (switchback design). Weighing steers 2 or 3 d at the beginning and end of the trial reduced variation and increased the probability of detecting differences in daily gain, gain/feed and protein efficiency when compared with a standard weighing method (once at the beginning and once at the end of the trial). Regressing 11 weekly weights on an average of one, two or three initial and final weights also reduced variation and increased the probability of detecting treatment differences. Regressions of weekly weights were more useful as the number of initial and final weights was decreased. Daily gain and gain/feed increased linearly (P less than .05) with protein level when BM or SBM was fed. A nonlinear model was used to predict protein requirement, maximum gain and relative protein values. There was a range in relative values for BM of 255 to 348% depending on the method of analysis used.

Analysis of Variance↗
PubMed1982

Relationship between brain mitochondrial hexokinase and neuronal function: comparable effects of 2-deoxy-D-glucose and thiopental.

Mitochondrially bound brain hexokinase is solubilized by anesthetics and this effect has been suggested to contribute to anesthesia. In the present investigation the influence of the metabolic inhibitor 2-deoxy-D-glucose (2-DOG) was studied. An isolated rat brain preparation was used to avoid the contribution of peripheral reactions. Isolated rat brains were perfused for 45 min with media containing 4 mmol/l glucose, 10 mmol/l 2-DOG and/or 0.4 mmol/l thiopental. The EEG was monitored and acetylcholine, 2-DOG and its 6-phosphate, as well as the intracellular distribution of hexokinase activity were determined in brain tissue. Soluble hexokinase activity in brain cortex was enhanced by 2-DOG, as also by thiopental, and even more pronounced by both drugs used together, Results from in vitro experiments suggest that solubilization of mitochondrial hexokinase after 2-DOG is mediated by intracellularly accumulated 2-DOG-6-phosphate. 2-DOG produced a significant impairment of neuronal activity, revealing EEG patterns similar to those caused by thiopental anesthesia. Cortical acetylcholine levels were elevated by 2-DOG, as well as by thiopental, and again both drugs showed an additive effect when used in combination. This effect which may be the result of an inhibition of acetylcholine release, was also detectable in mice in vivo after 5 g 2-DOG/kg i.p., whereas the same dose of 3-O-methylglucose had no effect. The results provide further evidence that mitochondrial hexokinase may be involved in the relationship between cerebral metabolism and brain function.

Animals↗