Attempts to demonstrate indirect T cell allorecognition of donor MHC peptides in transplant patients

Indirect T cell allorecognition has been shown to play an important role in the rejection of allografts in experimental animals. Although there has been much speculation as to its role in clinical transplantation, especially with regard to chronic rejection, indirect T cell allorecognition has been difficult to demonstrate in transplant patients. In this paper, we looked for in vitro T cell proliferation to synthetic peptides corresponding to donor HLA-A and HLA-B incompatible antigens. Twelve 15 amino acid peptides corresponding to the hypervariable regions of six of the most common HLA class I alleles in Caucasian populations (A1, A2, A3, B7, B8 and B44) were studied. Blood was taken from 12 adult patients following one or more episodes of acute kidney graft rejection, and from three pediatric patients undergoing chronic rejection of heart/lung transplants. The donor-recipient combinations were selected such that at least one of the six HLA antigens above was present in the donor and absent in the recipient. Peripheral blood mononuclear cells from these patients responded strongly in proliferation assays to phytohemagglutinin. However, none responded to the incompatible donor HLA peptides. Compartmentalization of responding T cells, the effects of immunosuppression, and assay sensitivity are discussed as possible explanations for the negative results.

Molecular genetics of beta-thalassaemia in Pakistan: a basis for prenatal diagnosis

Thalassaemia is the most common inherited disorder in Pakistan and there are very inadequate treatment facilities for over 4000 homozygotes born each year. Prevention of these disorders therefore forms an essential part of the management of this enormous health problem. We have characterized 1216 beta-thalassaemia alleles from the five major ethnic groups of Pakistan. The complete spectrum comprised 19 different mutations. There are important ethnic and regional differences in the prevalence of mutations. The five most common mutations, IVSI-5 (G-C) (37.3%), Fr 8-9 (+G) (25.9%), del 619 (7.0%), Fr 41-42 (-TTCT) (6.7%) and IVSI-1 (G-T) (5.4%), constitute 82.3% of the total. Fr 8-9 (+G) is the most common mutation in Northern Pakistan (41.3%), whereas IVSI-5 (G-C) is the most frequent mutation in Southern Pakistan (52.2%). Six subjects with transfusion-dependent thalassaemia major showed only a single mutant allele. One subject with transfusion-dependent thalassaemia major showed a novel 17 bp deletion involving Cd126-131. Our findings provide a comprehensive basis for carrying out prenatal diagnosis of thalassaemia in a geographical area where it is found in high frequency.

Prevalence of antibody to hepatitis C virus in Pakistani thalassaemics by particle agglutination test utilizing C 200 and C 22-3 viral antigen coated particles

Exposure to hepatitis C virus (HCV) and its effect on ALT levels was studied in 35 transfusion dependent cases of thalassaemia major. Twenty-one (60%) cases were anti HCV positive and also showed raised Alanine Transaminase (ALT) levels. Of 14 anti HCV negative, Hepatitis B Surface Antigen (HBs Ag) negative seven showed raised ALT levels, indicating the chances of acute viraemia. Thus there is an urgent need to start anti HCV screening on all blood donations.

Disseminated intravascular coagulation in acute leukaemias at first diagnosis

Haemorrhagic diathesis is the commonest cause of morbidity and mortality in acute leukaemias (AL). It is most commonly due to thrombocytopenia resulting from bone marrow failure. However, in a significant number of cases, disseminated intravascular coagulation (DIC) plays an important part. Previously it was thought that this mechanism was mainly confined to acute promyelocytic leukaemia (APL), but recently it has also been reported to occur in other subtypes of acute leukaemia. We report the results of a study carried out to find the incidence of DIC in various types of AL at the time of first diagnosis and in the absence of other recognisable causes. DIC was observed in 14(13.4%) cases out of 104 cases of AL studied. Nine out of 49(18.4%) cases of AML and 5 out of 55(9.1%) cases of acute lymphoblastic leukaemia (ALL) showed coagulation abnormalities consistent with DIC. Out of the 9 cases of AML showing DIC, 63 (66.67%) belonged to APL (FAB ME) subtype. Three (60%) out of 5 cases of ALL with DIC had T-cell immunophenotype. The results indicate that DIC may also occur in types of AL other than APL, particularly in T-ALL, and should be looked for.

Granulocytic sarcoma in patients with chronic myeloid leukaemia

Granulocytic sarcoma is an unusual variant of myeloid malignancy most commonly encountered in the course of chronic or acute myeloid leukaemia. Of 60 patients of chronic myeloid leukaemia studied over 21 months, we encountered 6 (10%) cases of granulocytic sarcoma. Four of these had granulocytic sarcoma on their first presentation. All those who were receiving hydroxyurea did not fare well but one who was put on DAT (daunorubicin, cyftosine arabinocide, 6 thioguanine)regimen went into remission with complete disappearance of lesions.

Evaluation of M/H ratio for screening of beta thalassaemia trait

This study was done to evaluate the efficiency of M/H ratio between the percentages of microcytic and hypochromic cells as a screening procedure for thalassaemia trait in Pakistani population. A total of 150 subjects, were included in this study. The analysis of results revealed that M/H ratio is a very sensitive index for beta thalassaemia trait. The sensitivity, predictive value and diagnostic accuracy of the M/H ratio for beta thalassaemia trait was 100%, 90.4% and 90.4% respectively. It also picked up all cases of beta thalassaemia trait with co-existent iron deficiency. It is therefore concluded that M/H ratio is an easy, reliable and sensitive index which can be used for mass screening of beta thalassaemia trait, particularly in a population where iron deficiency is also prevalent.

Blood lead levels and anemia in lead exposed workers

The effects of lead on haematological parameters were studied in 51 occupationally exposed individuals comprising of 27 lead furnace workers, 24 lead pellet handlers and 20 healthy age and service matched controls. Blood lead levels were estimated by atomic absorption spectrometer AAS-180-80 and haematological parameters by Technicon H.1 system. The lead furnace workers had highest blood lead levels (median 71.20 ug/dl, range 21.2-171.10 ug/dl) and low Hb (median 106 g/l, range 73-144 g/l) as compared to healthy subjects (median lead levels 29.80 ug/dl, range 10.20-54.10 ug/dl and Hb median 135 g/l, range 101-153 g/l). The workers handling pellets had moderately increased blood lead levels (median 45.50 ug/dl, range 8.50-130.6 ug/l) and low Hb (median 114 g/l, range 74-158 g/l). The furnace exposed workers had higher blood lead levels and low Hb compared to the lead pellet handlers. TRBC, Hct, MCV, MCH and MCHC did not reveal any significant difference in all groups. It is concluded that chronic lead exposure causes normocytic normochromic anaemia and shows a dose response relationship between lead levels and severity of anemia.

Serum ferritin levels in carriers of beta-thalassaemia trait

Hypochromic and microcytic red cell morphology is the most commonly encountered abnormality in a clinical laboratory. Most of such cases have iron deficiency anaemia. However, in Pakistan about 5% of the individuals with a hypochromic and microcytic blood picture have the beta-thalassaemia trait. These individuals are more than often in a positive iron balance. However iron deficiency (being common) may be associated with the beta-thalassaemia trait. This study of serum ferritin levels was carried out on 135 confirmed cases of the beta-thalassaemia trait. A ferritin assay was done by a radioimmunoassay technique. The results show that the level of serum ferritin in 100 (74%) cases was within normal limits, in 17 (12.6%) cases it was above the normal range, whereas in 18 (13.4%) cases the level was lower than normal. The importance of serum ferritin estimation in carriers of the beta-thalassaemia trait is highlighted.

Antibodies to the extractable nuclear antigens (ENA) in Pakistani patients with systemic rheumatic disease

Autoantibodies to the saline extracts of cells are being used as diagnostic and prognostic markers in the investigation of patients with suspected systemic rheumatic disease. These are also called antibodies to the extractable nuclear antigens or anti ENA antibodies. We used saline extracts of human spleen cells and rabbit thymus extract to detect six subtypes of anti ENA antibodies, namely anti SSA (anti Sjogren's syndrome A), anti SSB (anti Sjogren's syndrome B), anti RNP (anti Ribonucleoprotein), anti Sm (anti Smith), anti Jo-1 (anti Jo-1) and anti Scl 70 (anti Systemic sclerosis 70) antibodies. Two hundred and thirty-seven patients' sera were screened in the department of Immunology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, over a period of 16 months. Fifty-seven were positive for auto antibodies, of which 26 had anti SSA antibodies, 12 anti SSA+ anti RNP+ anti Sm antibodies, 7 anti RNP+ anti Sm antibodies, 6 anti SSA+ anti SSB antibodies, 5 anti SSA+ anti RNP antibodies while one patient showed only anti RNP antibody. The detection of the anti ENA antibodies was specially helpful in diagnosing patients with systemic lupus erythematosis presenting with atypical features and with mixed connective tissue disease.

Screening for chronic lead poisoning in lead factory workers

One hundred and forty-nine lead factory workers comprising of 46 fume exposed, 78 handling lead materials and 25 controls were screened for chronic lead poisoning. Blood lead level was determined by atomic absorption spectrometery and urinary ALA by ion-exchange chromatography. Fume exposed workers had significantly higher (P < 0.01) blood lead (median 61.20 micrograms/dl, range 21.20-171.10 micrograms/dl) and urinary ALA levels (median 4.10 mg/l, range 01.0-22.9 mg/l) than workers handling lead materials and controls. Urinary ALA was found to be a more sensitive and specific test for lead poisoning than estimation of blood lead levels.

Design and structural requirements of potent peptidomimetic inhibitors of p21ras farnesyltransferase

Cysteine farnesylation of the ras oncogene product, p21ras, on its carboxyl-terminal CA1A2X box (C = cysteine, A = aliphatic, and X = methionine or serine) is required for its transforming activity. p21ras farnesyltransferase (FTase), the enzyme responsible or this important posttranslational modification can be inhibited by simple CA1A2X peptides. We have synthesized a family of CA1A2X peptidomimetics where the central 2 aliphatic amino acids are replaced by a variety of spacer groups with different shapes and conformational characteristics to investigate the structural requirements of these inhibitors. The biological activities of CA1A2X peptidomimetics, where the dipeptide "A1A2" is replaced by 3- or 4-aminomethylbenzoic acid (AMBA) and 3- or 4-aminobenzoic acid (ABA), are evaluated in a p21ras FTase inhibitory assay. Peptidomimetics Cys-4-ABA-Met and Cys-3-AMBA-Met contain spacers that provide good distance correspondence of the carboxylate and ammonium separation with that of the parent KB p21ras tetrapeptide, Cys-Val-Ile-Met, and are as potent FTase inhibitors (IC50 values of 50 and 100 nM, respectively). In contrast, replacing the central dipeptide with 4-AMBA reduced FTase inhibitory activity by 17-fold whereas replacement by 3-ABA reduces inhibitory activity of the peptidomimetics by 43-fold. Cys-4-ABA-Met (IC50 = 50 nM) is 128 times more potent as a p21ras FTase inhibitor than Cys-3-ABA-Met (IC50 = 6400 nM), yet these two peptidomimetics differ only in the substitution pattern around the phenyl ring. These results coupled with computer modeling studies demonstrate that the interaction between FTase and the peptidomimetics requires precise structural and conformational characteristics; in particular, correct positioning of the Cys and Met must be respected. Furthermore, Cys-3-AMBA-Met and Cys-4-ABA-Met are true inhibitors of p21ras FTase since they are not farnesylated by this enzyme, in contrast to Cys-Val-Ile-Met, which inhibits the enzyme by acting as alternative substrate. Computer modeling studies of the potent FTase inhibitor Cys-4-ABA-Met show that a folded conformation, where the thiol and carboxylate groups are close, is not possible. Therefore a beta-turn conformation that would result in the simultaneous coordination of the Cys-thiol and Met-carboxylate to zinc ion is not important for inhibition of p21ras FTase, as previously suggested.

A low molecular weight peptide from snow mold with epitopic homology to the winter flounder antifreeze protein

Evidence for a small size protein (ca. 3500 kDa) exhibiting epitopic homology to the Atlantic winter flounder antifreeze protein (AFP) is found in the snow molds Coprinus psychromorbidus, Myriosclerotinia borealis, and Typhula incarnata. The protein shows strong cross-reactivity with antisera specific for the flounder AFP. Preliminary studies suggest that the protein is synthesized in response to lowering the culture temperature, and that it is membrane associated and, therefore, may function in an analogous capacity to the fish AFP. Also, the protein is shown to have antifreeze properties as determined by nuclear magnetic resonance microimaging experiments.

Prevalence of heterozygous beta-thalassemia in northern areas of Pakistan

Five hundred apparently healthy adults from northern parts of Punjab and NWFP were screened for the prevalence of heterozygous beta-thalassemia. The trait was detected in all ethnic groups with an overall prevalence rate of 5.4% (27/500). Pathans had significantly (P less than 0.02) higher prevalence rate (7.96%) than Punjabis (3.26%).

Alpha-thalassaemia: prevalence and pattern in northern Pakistan

The level of Hb Bart's is directly related to the inheritance of alpha-thalassaemia gene. Hb electrophoresis for Hb Bart's in the cord blood is a very simple method of finding out the prevalence of alpha-thalassaemia gene in a given population. A study was, therefore, carried out to find out the prevalence of alpha-thalassaemia gene in the population of northern Pakistan by estimating the concentration of Hb Bart's in 500 cord blood samples during the period 1986-87 at AFIP Rawalpindi. Hb Bart's was detected in 12 neonates, thus indicating a rate of 2.4% of general population as carrier of alpha-thalassaemia gene. Two distinct groups were recognized. The first group was composed of 9 (75%) neonates, in which Hb Bart's levels varied between 2.0% to 3.5%, while the second group of 3 neonates (25%) showed a level of 5.8% to 6.3%. The former group was considered to be carrying alpha-thalassaemia-2 gene and the latter group as carrier of alpha-thalassaemia-1 gene. Neither Hb H disease nor Hb Bart's hydrops foetalis syndrome was detected in this series.

Results of balloon pulmonary valvuloplasty as a palliative procedure in tetralogy of Fallot

Balloon pulmonary valvuloplasty was attempted in 67 patients with tetralogy of Fallot at a median age of 5 months (range 0.03 to 52 months) for relief of cyanosis. In three patients, the valve could not be crossed and an aortopulmonary shunt was performed. In 35 patients, follow-up angiography was performed 3 to 30 months (average 12) after valvuloplasty. In 24 of these 35 patients (group A), the stenosis had been adequately palliated by valvuloplasty; the other 11 patients (group B) had required an aortopulmonary shunt 1 month (range 0 to 3 months) after valvuloplasty. The two groups were similar (p greater than 0.1) with respect to age at valvuloplasty, pulmonary anulus diameter, ratio of pulmonary artery to descending aorta diameter before valvuloplasty and interval to follow-up angiography. In contrast to patients in group B, patients in group A had a significant immediate improvement in systemic arterial oxygen saturation (p less than 0.01) and a significant increase in pulmonary anulus diameter at follow-up angiography (p less than 0.001). The growth of the branch pulmonary arteries was similar (p greater than 0.1) in the two groups. Among 42 patients who have had surgical correction, a transannular patch for right ventricular outflow tract reconstruction was used in 27 (64%); there was no difference between groups A and B with respect to its use. Eight patients died (three after repair) and death could not be directly attributed to valvuloplasty in any. Balloon valvuloplasty promotes growth of the pulmonary valve anulus and pulmonary arteries and is a useful alternative to an aortopulmonary shunt in patients with small pulmonary arteries or associated complex intracardiac defects.

Culture conditions for induction of green plants from barley microspores by anther culture methods

With barley a large variation in frequency of plant formation from microspores of spikes from the same plant has been observed. The highest frequency of plant formation was obtained when culturing anthers in the dark on a high Ficoll medium containing 2,4-D and kinetin to induce proembryo (or callus) formation. Subsequently the proembryos or calli were cultured in dim light on a high Ficoll-high sugar medium containing IBA and kinetin. Finally the embryos were transferred to a starch agar medium. A maximum of 13 green plants were obtained from microspores of a single anther.The ratios of green to albino microspore derived plants varied from 9∶1 to 1∶9 depending on culture conditions. Under anaerobic conditions, lactic acid and other organic acids may have damaged the organelles in the cells resulting in the formation of albino plants. Thus, direct embryogenesis by using a well-buffered, high Ficoll-high sugar medium and proper aeration are essential for obtaining high frequency of green plants from microspores.

Biopharmaceutical studies of 3-substituted isatin derivatives

The metabolic fate of isatin hydrazone (Ia), isatin-3-thiosemicarbazone (Ib), isatin-3-semicarbazone (Ic), isatin-3-phenylhydrazone (Id), isatin oxime (Ie) and 3-hydroxy-3-acetonyl oxindole (II) was studied in rabbits. The compounds were administered orally in the dose of 300 mg/kg body wt. Isatin anthranilic acid, tryptophan and nicotinic acid were identified as the major metabolites excreted in urine. The 3-hydroxy-3-acetonyl oxindole (II) gave on additional metabolite, oxindole. The major metabolites were separated and identified unambiguously on thin layer silica gel plate. Metabolic pathways have been proposed to explain the biotransformation of the compounds investigated.

Design and cloning of a synthetic gene for the flounder antifreeze protein and its expression in plant cells

A synthetic gene coding for the winter flounder antifreeze protein (AFP) has been constructed. A new strategy for the synthesis has been employed such that one strand of the duplex was chemically synthesized and the other was produced enzymatically by chain extension. The chemically synthesized blocks were constructed so that the second strand was self-priming. The resulting DNA fragment was incorporated into the vector, pGCS1, which contained a translational fusion of the sequence encoding AFP and the N terminus of cat (encoding chloramphenicol acetyltransferase, CAT), under the control of the cauliflower mosaic virus 35S promoter. This plasmid was introduced into protoplasts of corn (var. Black Mexican Sweet) by electroporation. Production of the fusion peptide was monitored by CAT assay and Western blotting with antisera to AFP and CAT.

Chromosomal pattern in acute lymphoblastic leukaemia

Analysis of the chromosomal changes in various neoplasia is being increasingly carried out not only to evaluate its relationship with the prognosis and biological behaviour of the tumour but also for diagnostic purposes in some cases. Leukaemias are one such group of haematological malignancies which have been most extensively studied in this regard. Karyotypic analysis with Giemsa banding technique was carried out in 35 consecutive cases of Acute Lymphoblastic Leukaemia. Eighteen cases were in children (less than 15 years age) and 17 cases were in adults. M.F. ratio was 1.8:1 FAB classification of these cases showed 31 cases of L1 type and 4 cases of L2 type including one case of T-ALL. Fifteen cases (43%) had no karyotypic abnormality, 6 cases (17%) showed pseudodiploidy, one case each having (-20 + 21), t (9:22), (+ 2-6), (-6 + 8), while two cases had 6 q-.13 cases (37%) showed hyperdiploidy with 6 cases showing trisomy 8 alone, one case (+ 8 + 21), one case trisomy 18, one case + 15(r), one case trisomy 21 plus t (9:22) and one case with trisomy 21 only. Two cases showed more complex abnormalities i.e. + 2 + 8, t (13:22) and -11 + MR + Min + Min. There was one (3%) case of hypodiploidy showing monosomy 6. The above findings are in agreement with studies carried out in other countries except t (13:22) which is rather a scarcely reported abnormality.

Isoniazid acetylation and polymorphism in humans

Phenotypes of slow and fast acetylators of isoniazid (INH) were determined in 157 subjects (80 normals and 77 patients with tuberculosis) from the twin cities of Rawalpindi and Islamabad. Plasma INH concentrations were determined chemically six hours after the drug ingestion. The findings indicate that 31.8% subjects were fast acetylators of the drug.

Visceral leishmaniasis: a seroepidemiological study of 289 children from endemic foci in Azad Jammu and Kashmir by indirect fluorescent antibody technique

Between January '85 and August '87, 22 cases of VL were seen at National Institute of Health, Islamabad. Three (14.6%) came from the previously known endemic region of Gilgit, 15 (68.1%) from different localities in Azad Jammu and Kashmir (AJ&K), and 4 (17.3%) from neighbouring foci in NWFP and Punjab. Mean age of the patients was 4.2 years, (Range, 10 months to 57 years) median 2.5 years and mode 2 years. High levels of Leishmania antibodies were detected by Indirect Immunofluorescent Antibody Technique (IFAT) in all cases. Leishmania were isolated from bone marrow aspirates of 2 patients and isoenzyme characterization performed in one of these, the organism was typed as Leishmania infantum sensu stricto. Sera from 289 children residing in 5 endemic localities in AJ&K was tested for Leishmania specific antibodies by IFAT and low levels of these antibodies were detected in 15.4% of the cases.

Incidence of aflatoxin contamination in non-perishable food commodities

To assess the incidence of aflatoxins contamination in different commodities, a representative countrywide study was conducted. One hundred composed samples of cereals, grains, spices, condiments and refined and raw sugars were analysed for aflatoxin B1, B2, G1 and G2. The moisture contents of all the food samples were also invariably determined. Only 6% of the samples namely maize and red chillies were found to be contaminated with aflatoxin B1 and B2 respectively. The percentage of samples contaminated among maize was 41.6 and the level of aflatoxin B1 ranged between 11.12 micrograms/Kg to 82.33 micrograms/Kg. In red chillies contamination was 25% and the level of aflatoxin B2 was 41.67 micrograms/Kg.

Convulsions caused by endrin poisoning in Pakistan

From July through September 1984, acute convulsions caused by endrin poisoning occurred in the subdistrict of Talagang, Attock District, Punjab province, Pakistan. Eighteen of the 21 affected villages were surveyed; 70% of the cases for which ages were known (106 of 152) were in children 1 to 9 years of age; 9.8% of all affected persons (19 of 194) died. The outbreak occurred in villages on the main roads of the subdistrict and peaked in early September. Endrin was detected in the blood of 12 of 18 patients with a history of convulsions but was not found in the blood of four hospitalized control patients. One composite sugar sample taken from the homes of three persons had an endrin level of 0.04 ppm. Because of the high toxicity, repeated association with large-scale outbreaks of neurologic illness, and the difficulties of monitoring distribution, endrin should not be used for agricultural purposes.

A mathematical model with young predation

We generalize the model of [21] in which the author considered a predator-prey system with predators eating only the young ones (or eggs) of the prey species. The prime assumption of the present paper is that the birth rate (per unit individual per unit time) of predators depends not only on the current prey egg-level but also on all previous prey egg-levels. It is seen that under this assumption an otherwise stable system may be stable as well as unstable leading to the conclusion that young predation with time delay is less stable than without it. Finally for the model of [21] we prove a result which shows that large predation rates help in the co-existence of both predator and prey species.

OKB7 recognizes antigen on T-cell malignancies

This article describes the pattern of OKB7 positivity in 49 cases of lymphoid malignancies (31 ALL, 17 chronic lymphocytic leukemia (CLL), 1 HCL). The authors have observed that it reacted with 4 out of 5 cases of T-ALL and 8 out of 17 cases of B-CLL. Incidentally all cases of OKB7+ T-ALL were also CALLA+. One case of HCL and 26 cases of non-T-ALL did not react with this antibody. The authors suggest that OKB7 is not specific for B-lineage and many cases of T-ALL may cross-react with it. However, it may be useful for identification of peculiar T-ALL phenotypes (T+, OKB7+, and CALLA+).

Permeabilizing soybean protoplasts to macromolecules using electroporation and hypotonic shock

The percentage of soybean cell culture protoplasts permeabilized by electroporation was dependent on the voltage and the number of successive pulses that were applied. Best results were obtained with two 50 milliseconds, 400 volts per centimeter pulses after which 78% of the surviving protoplasts had been permeabilized to the fluorescent dye calcein. Quantitation of the volume of extracellular fluid taken up was performed using radioactive inulin (molecular weight 5000-5500). Typically between 20 and 40 nanoliters of fluid was taken up by 10(6) protoplasts. Electroporation and hypotonic shock treatments (M Saleem, AJ Cutler 1986 J Plant Physiol 124: 11-21) were compared with respect to the volume of fluid taken up under optimum conditions. Electroporation produced 10 times more uptake than hypotonic shock treatment. In all experiments there was a direct relationship between the number of protoplasts lysed and both the amount of fluid taken up and the percentage of surviving protoplasts that were permeabilized.