Site-specific frameshift mutagenesis by a propanodeoxyguanosine adduct positioned in the (CpG)4 hot-spot of Salmonella typhimurium hisD3052 carried on an M13 vector

Malondialdehyde induces frameshift mutations in Salmonella typhimurium strain hisD3052. The ability of propanodeoxyguanosine (PdG), a structural analog of the major malondialdehyde-deoxyguanosine adduct, to induce site-specific frameshift mutations was tested in the (CpG)4 hot-spot of hisD3052 carried on an M13 vector (M13MB102). PdG was introduced at position 6248 of duplex M13MB102 by ligation of the oligonucleotide 5'-CGC(PdG)CGGCATG-3' into a heteroduplex containing an 11-nucleotide gap in the (-)-strand between the SphI and BssHII restriction sites and deoxyuridine in place of thymidine in the (+)-strand. Ligation proceeded with 70% efficiency, and closed circular duplex DNA molecules were isolated in 40% yield. The adducted genome was sensitive to cleavage by SphI but resistant to cleavage by BssHII. Transformation of Escherichia coli strain JM105 with adducted M13MB102 led to 25% reduced survival relative to unadducted M13MB102 and produced frameshift mutations in 2.5% of the progeny phage. All of the mutations were deletions, and 70% occurred by deletion of CpG. Unadducted genomes exhibited a 40-fold lower mutation frequency, and all the mutations were single-base deletions at the sites of ligation of the 11-mer. These results illustrate that PdG, a structural analog of the major malondialdehyde-deoxyguanosine adduct, induces frameshift mutations in M13MB102 and that single-stranded nicks are efficient premutagenic lesions in this recombinant bacteriophage.

Lipid-laden macrophages in bone marrow of leprosy patients

While conducting a study to observe bone marrow cytomorphological changes in multibacillary leprosy, lipid laden macrophages as seen in sphingolipidoses were noted. The present study was planned to observe the occurrence and morphological characterization of these macrophages in various types of leprosy. Bone marrow records from 48 cases of paucibacillary and 72 cases of multibacillary leprosy were analysed. The macrophages accounting at the most for 3.5% of marrow cells were observed in 5 cases of paucibacillary and 43 cases of multibacillary leprosy with a maximum incidence being observed in patients with ENL (16/17). The lipid present in the cytoplasm of these cells could be derived from the lipid of the cell wall of Mycobacterium leprae. To the best of our knowledge, these cells have not been reported in leprosy so far.

Prevalence & spectrum of congenital malformations in a prospective study at a teaching hospital

A prospective survey for congenital malformations at birth, at a teaching hospital, over a period of two and half years on 9405 consecutive single births has shown that prevalence of major congenital malformations in live births was 1.6 per cent and in still births 16.4 per cent. There was no significant difference in the prevalence of congenital malformations between Hindus (2.0%) and Muslims (2.7%) but amongst Muslims with consanguinity the prevalence of congenital malformation was 4.6 per cent compared to 2.3 per cent in non-consanguineous Muslim spouses (P less than 0.05). Open neural tube defect was the single most common anomaly (31.7% of all malformations) occurring at a rate of 4.7 per 1000 single births, with equal prevalence of anencephaly and meningomyelocoele. Case control study showed that history of concomitant medical illness, drug intake during the first trimester, threatened abortion, hydramnios and pre-eclamptic toxaemia in the current pregnancy were significantly associated with the occurrence of congenital malformations.

Sulfhydryl-dependent attachment of Treponema denticola to laminin and other proteins

Attachment of Treponema denticola ATCC 35405 to laminin, a major basement membrane protein, and to other proteins was studied. Microdilution plates were coated with the proteins, and the attachment of T. denticola was measured by the enzyme-linked immunosorbent assay technique. Compared with bovine serum albumin (BSA), T. denticola had a high affinity to laminin, fibronectin, fibrinogen, and gelatin, as well as to type I and type IV collagens. Attachment to RGD peptide (Gly-Arg-Gly-Asp-Ser, the integrin recognition sequence) was only about 30% of that to laminin and was comparable to attachment to BSA. Tests with laminin fragments obtained through elastase digestion showed that the spirochetes attached well to an A-chain 140-kDa fragment involved in eukaryote cell attachment but did not attach to a 50-kDa fragment that includes the heparin binding site. Pretreatment of T. denticola with soluble laminin, fibronectin, gelatin, BSA, or fibrinogen had no effect on the attachment of the bacteria to laminin or fibronectin. A wide variety of compounds were tested for their possible inhibitory actions on the attachment. While most treatments of T. denticola ATCC 35405 had little or no effect on the attachment to proteins, sulfhydryl reagents p-chloromercuribenzoic acid (pCMBA) and oxidized glutathione inhibited the attachment by 70 to 99%, depending on the protein. When T. denticola was first allowed to attach to proteins, addition of pCMBA or oxidized glutathione could no longer reverse the attachment. Heat treatment of the spirochetes also markedly reduced the attachment to laminin, gelatin, and fibrinogen but not to BSA. Mixed glycosidase treatment of the spirochetes inhibited the attachment by 20 to 80%. None of the above treatments of the substrate proteins had any marked effect on the spirochete attachment. The results indicate that T. denticola has the capacity to bind to many different kinds of proteins by utilizing specific attachment mechanisms. The binding appears to involve protein SH groups and/or carbohydrate residues on the surface of T. denticola.

Isoproterenol fails to produce myocardial necrosis in streptozotocin-induced diabetic rats

Biochemical alterations in the hearts of non-diabetic and 5 weeks of streptozotocin-induced diabetic rats following isoproterenol (ISO) administration were compared. Serum lactate dehydrogenase (LDH) and myocardial adenosine triphosphate (ATP), creatine phosphate (CP), lactate and glycogen were used as indices of myocardial injury. Hearts from diabetic rats (blood glucose greater than 350 mg/dl), before ISO administration, had normal lactate levels but significantly low high-energy phosphate (HEP) levels and high glycogen levels in comparison to non-diabetic rats. No difference was observed in serum LDH levels between these two groups. ISO administration to non-diabetic rats caused myocardial necrosis as evidenced by a significant depletion of myocardial glycogen and HEPs along with significant myocardial lactate accumulation and an increase in serum LDH. However, the hearts from diabetic rats failed to show any significant HEP depletion, accumulation of lactate and leakage of LDH into serum following ISO-administration, though myocardial glycogen level was significantly lowered. These observations, in conjunction with earlier reports, point to the hypothesis that, in diabetes, there are certain alterations in the sarcolemma which hamper the process by which ISO causes myocardial necrosis.

Patterns of erythropoiesis and anaemia in leprosy

A total of 128 leprosy patients were investigated for the morphological type of anaemia, the underlying disturbances in iron metabolism and patterns of erythropoiesis and other cytomorphological changes in the bone marrow. The anaemia was a mild to moderate degree in paucibacillary (PB) leprosy, while in multibacillary (MB) leprosy it was of a severe degree. Iron deficiency was observed in only a few patients. Impaired iron utilization as observed in a anaemia of a chronic disorder was a common finding in MB leprosy (41.7%) and more so in new cases (50%). Megaloblastic erythropoiesis was also more frequent in MB leprosy (45.2%) as compared to PB leprosy (16%), accounting for the severe degree of anaemia in the former type. In 17.2% of the total patients (MB, 21.4%; PB, 9%) both megaloblastic erythropoiesis and features of impaired iron utilization were observed in bone marrow. Disturbances in iron metabolism and erythropoiesis were also observed but to a lesser degree in patients receiving specific antileprosy treatment. Irrespective of the type of disease and duration of treatment, increasing frequency of acid-fast bacillia (AFB) positivity and granulomas was observed in the bone marrow with an increasing severity of anaemia.

Hypermagnesemia following aluminum phosphide poisoning

Aluminum phosphide (ALP) is highly toxic to the lungs, heart and blood vessels causing pulmonary edema, shock and arrhythmias. There is massive focal myocardial damage resulting in raised cardiac enzymes. This study included 92 patients of proven ALP poisoning. The age varied between 20-50 years and the majority (74) were females. Clinical manifestations were nausea and vomiting (92), dyspnea and palpitation (72 each), cyanosis (54), hypotension (32) and shock (46) etc. Cardiac arrhythmias were present in 80 cases and hypermagnesemia in 78 patients. Mean serum magnesium level (1.95 +/- 0.18 mE/l) was significantly (p less than 0.01) raised compared to mean magnesium level in control subjects (1.62 +/- 0.26 mEq/l). Hypermagnesemia results from myocardial and liver damage and to our knowledge has not been described in the literature. Of 92 cases studied, 66 died, 60 of whom died within 24 hours of ALP ingestion. Treatment is supportive.

Expression of IgG Fc receptor antigens in placenta and on endothelial cells in humans. An immunohistochemical study

Expression of leukocyte IgG Fc receptor (Fc gamma R) antigens by placenta, endothelial cells (EC) of normal tissues, and ECs of kidney and skin from subjects with immune complex diseases was studied immunohistochemically using anti-Fc gamma R monoclonal antibodies (MAb). Monoclonal antibodies against all three leukocyte Fc gamma R classes stained placental villous macrophages. Placental villous trophoblasts were stained intensely by anti-Fc gamma RIII MAb 3G8, while both anti-Fc gamma RI (MAb 32) and anti-Fc gamma RII MAbs IV3, KU79, CIKM5, 2E1, KB61, and 41H16) antibodies did not react with these cells. Anti-Fc gamma RII MAbs IV3, KU79, CIKM5, 2E1, KB61, and 41H16 immunostained placental villous capillary EC, in contrast to anti-Fc gamma RI MAb 32 and anti-Fc gamma RIII MAb 3G8, CLB-Granl, and B73.1, which did not bind. Anti-Fc gamma RI MAb 32, anti-Fc gamma RII MAb IV3 and CIKM5, and anti-Fc gamma RIII MAb 3G8 did not react with the ECs of tonsil, liver, kidney, spleen, intestine, lung, or uterus. Similarly no EC staining was seen with these four MAbs in 14 skin and 14 kidney biopsies from subjects with immune-complex diseases. Fc gamma R antigens are expressed constitutively only by placental villous ECs and are not induced on nonplacental ECs by immune-complex-mediated diseases.

Patterns of erythropoiesis and anaemia in malaria

Of 138 patients with malaria, 90 were found to be having Plasmodium falciparum in their peripheral blood smears. Megaloblastosis alone or in combination with the other patterns of erythropoiesis was observed in 82.1 percent cases of chronic P. falciparum malaria as compared to 36.3 and 26.5 per cent cases of acute P. falciparum and P. vivax malaria respectively. Iron deficiency was observed in 15.5 percent cases of chronic P. falciparum, 18.2 per cent cases of acute P. falciparum and 13.3 per cent patients of P. vivax infection. Of patients with chronic falciparum malaria, 33.3 percent revealed features of both megaloblastosis and defective iron utilization and transient hypoplasia of marrow was observed in 8.9 per cent of these cases.

Comparative evaluation of marginal leakage of different types of silver amalgam alloys in vitro--a microfluoroscopic study

A study was carried out in vitro to evaluate the amount of microleakage using seven different Silver amalgam alloy using Fluorescein dye. Among the high copper alloy used in this study, the admixed alloy showed least marginal leakage followed by the high copper lathecut alloy and the high copper spherical alloy. It was also observed that the marginal penetration of the conventional alloy are much more than the high copper alloy.

Choline deficiency activates phospholipases A2 and C in rat liver without affecting the activity of protein kinase C

There is evidence to suggest that liver tumor promoters exert their effect through the interference of signal transduction in hepatic cells. Both phospholipase A(2) and phospholipase C play important roles in the generation of second messengers and in the activation of Ca(2+), phospholipid-dependent protein kinase C. Using male Sprague-Dawley rats, we investigated whether liver tumor-promoting regimens of a choline-deficient diet and phenobarbital alter the activities of phospholipase A(2) and phospholipase C in the liver, and extended the study to determine the effect of a choline-deficient diet on protein kinase C activities. Feeding a choline-deficient diet for 1 week increased the activities of both phospholipase A(2) (50%) and phospholipase C (22%), and the activities of both enzymes were more than doubled after 4 weeks. Feeding a phenobarbital diet resulted in a slight decrease in phospholipase A(2) activities at 4 weeks but no significant changes in PLC activities. The protein kinase C activities and its distribution between soluble and particulate fractions remained unchanged after 1, 2, and 4 weeks feeding of a choline-deficient diet. Thus, activation of both phospholipase A(2) and C is distinct for a choline-deficient diet, not shared by phenobarbital diet. Increased activities of these enzymes were not associated with the activation of protein kinase C under the present experimental condition.

Clara cell 10 kDa protein (CC10): comparison of structure and function to uteroglobin

The cellular localization, functional activities and structures of rat and human Clara cell 10 kDa proteins (CC10) are compared to rabbit uteroglobin. CC10 is present exclusively in the non-ciliated cells of the surface epithelium of the pulmonary airways, whereas uteroglobin is reported to be present in the lung and reproductive organs. There is about 55% identity between the amino acid sequences of rat CC10 and either rabbit uteroglobin or human CC10. The latter two have 61% identity. Using the known structure of uteroglobin as the model, correlations between the structure and function for this group of proteins are made. Substitution of the residues for the rat and human CC10 into the structure of uteroglobin suggests that these proteins may be members of a structurally homologous family. Some of the functional differences may be due to distortion of the hydrophobic pocket in the dimeric protein and a surface hypervariability located on one contiguous helix and beta turn. Rat CC10 and rabbit uteroglobin both, nearly equally, inhibit papain and bind progesterone. Human CC10 does not inhibit papain and has markedly lower progesterone binding (4.6% of rabbit uteroglobin). Antiinflammatory activity of synthetic peptides corresponding to a homologous sequence region of uteroglobin and the two Clara cell proteins was tested. The region chosen has sequence similarity to lipocortin I. The peptides not only failed to inhibit carrageenan-induced foot pad swelling but exacerbated it. All three proteins inhibit pancreatic phospholipase A2. The phospholipase A2 inhibitory effect of CC10 may be important in regulating the inflammatory responses in the lung.

Circulating iso and auto antibodies to human spermatozoa in infertility

Blood samples from 50 couples of unexplained primary infertility and 25 healthy fertile couples were tested for antispermatozoa antibodies (ASA) by gelatin agglutination test and sperm immobilising complement dependent cytotoxicity test. The incidence of sperm agglutinating and sperm immobilising antibodies was found to be 14 per cent and 10 per cent respectively in infertile couples. Agglutinating antibodies were detected in 18 per cent males and 16 per cent of females while cytotoxic antibodies were found in 14 per cent males and 10 per cent of females. Only 4 per cent of the normal fertile couples taken as a control group showed positive ASA, hence the difference in incidence of positive ASA between the infertile and fertile couples was found to be statistically significant. Also, the agglutination test was observed to be more sensitive than the cytotoxicity test.

Effects of a choline-deficient diet and a hypolipidemic agent on single glutathione S-transferase placental form-positive hepatocytes in rat liver

Using the placental form of glutathione S-transferase (GST-P) as a marker of carcinogen-initiated hepatocytes, we investigated how a choline-deficient (CD) diet and BR931, a carcinogenic hypolipidemic agent, modify populations of single GST-P-positive hepatocytes. The liver of male Fischer rats (6-7 weeks old) fed a CS or basal diet contained mostly single or double GST-P-positive hepatocytes. Feeding a CD diet for 2-4 weeks led to increases in the number of aggregates of two and three GST-P-positive hepatocytes. By 8-12 weeks, there was an emergence of discrete foci of GST-P-positive hepatocytes consisting of more than 20 hepatocytes. Feeding a BR931 diet for 4-8 weeks resulted in no significant change in the number of single GST-P-positive hepatocytes in the liver as compared to feeding a basal diet. It is suggested that single GST-P-positive hepatocytes in the liver of relatively young rats maintained on a commercial diet may represent endogenously initiated cells. A CD diet promotes endogenously initiated cells to form larger aggregates or foci of GST-P-positive cells.

Formation of UDP-2-acetamido-2-deoxy-L-galactose and UDP-2-acetamido-2-deoxy-L-galacturonic acid by Pseudomonas aeruginosa

The O-specific polysaccharide from the lipopolysaccharide of Pseudomonas aeruginosa NCTC 8505 (IATS serotype O:3) consists of a tetrasaccharide repeating unit comprising L-rhamnose, N-acetyl-D-glucosamine (GlcNAc), bacillosamine, and N-acetyl-L-galactosaminuronic acid (L-GalNAcA) (Y. Tahara and S. G. Wilkinson, Eur. J. Biochem. 134:299-304, 1983). Incubation of GlcN or UDP-GlcNAc with cell extracts or EDTA-treated cells of P. aeruginosa NCTC 8505 yielded a mixture of UDP-ManNAc, UDP-GalNAc, UDP-GlcNAcA, UDP-ManNAcA, UDP-L-GalNAc, and UDP-L-GalNAcA. The last two compounds, here identified for the first time, may be intermediates in the synthesis of the L-GalNAcA moiety of the O-specific portion of the lipopolysaccharide of P. aeruginosa.

Cloning of Bacteroides gingivalis surface antigens involved in adherence

Despite the acknowledge importance of Bacteroides gingivalis as a periodontal pathogen, relatively little is known about the molecular basis for its pathogenicity. Recombinant DNA technology has created the opportunity to identify and characterize the virulence determinants. A Bact. gingivalis library was prepared in Escherichia coli JM83 with the vector pUC18. The library was screened for surface antigens by colony immunoblot and 337 putative surface antigen recombinants were identified. Two of these clones were found to have haemagglutinating activity. Antiserum raised against one of these clones reacted with a 43 kDa Bact. gingivalis protein that has haemagglutinating activity.

Implantation of fetal thymus and sympathetic ganglion within the anterior eye chamber in mice, to study neuro-immune interaction in thymic development

In this study 13- to 14-day fetal thymic lobes were implanted within the anterior eye chambers in mice either with or without a syngeneic newborn sympathetic ganglion. It was observed after 6 weeks of implantation that the thymic lobes that grew with the ganglia had fewer lymphoid cells than their counterparts which were grown without the ganglia. The cells that developed within the thymic lobes were Thy-1- and peanut agglutinin-positive. The thymic lobes that grew with sympathetic ganglia also showed the presence of adrenergic nerves, perhaps due to reinnervation of the thymic grafts from the ganglia.

Bacteroides gingivalis vesicles mediate attachment of streptococci to serum-coated hydroxyapatite

Outer membrane vesicles purified from Bacteroides gingivalis culture supernatant bound to serum coated hydroxyapatite (SeHA). The immobilized vesicles served as receptors for a number of species of oral streptococci. The binding of Streptococcus sanguis 12 to SeHA was increased 10 times by the vesicles. Vesicle-associated binding increased proportionally with an increase in the number of bound vesicles. Arginine and lactose both partially reduced binding of S. sanguis. Heating the vesicles destroyed their binding ability whereas heating S. sanguis reduced but did not eliminate vesicle-mediated binding.

Inhibition of rat liver microsomal estrogen 2-hydroxylase by 2-methoxyestrogens

The inhibition of estrogen 2-hydroxylase by 2-methoxyestrogens was demonstrated in screening assays and has been further investigated under initial velocity conditions. The ability of 2-methoxyestradiol and 2-methoxyestrone to block the conversion of estradiol to 2-hydroxyestradiol by male rat liver microsomal preparations was determined by measuring the release of 3H2O from [2-3H]estradiol. The apparent Kis were found to be 34.86 microM for 2-methoxyestradiol and 18.65 microM for the methoxyestrone, with the apparent Km for the substrate estradiol in these essays of 3.21 microM. Mixed inhibition studies with the methoxyestrogens and 2,4-dibromoestradiol, an effective estrogen 2-hydroxylase inhibitor, in male rat liver microsomes resulted in Dixon plots consisting of a series of parallel lines. Thus, methoxyestrogens and 2,4-dibromoestradiol are mutually exclusive inhibitors, i.e., the binding of one compound to the enzyme interferes with the binding of the other. These results indicate that the compounds are interacting at the same enzymatic site. Finally, a method utilized to measure estrogen 2-hydroxylase activity in vitro is a radioenzymatic assay involving addition of catechol o-methyltransferase (COMT) and radiolabeled S-adenosylmethionine, and the amount of catechol estrogens formed is determined by the amount of radiolabeled methoxyestrogens isolated. The results described here demonstrate inhibition of estrogen 2-hydroxylase by methoxyestrogens; however, under enzymatic conditions of low product formation, the estrogen 2-hydroxylase inhibitory effect of catechol estrogen products from the radioenzymatic assay would be insignificant. Thus, these interactions of methoxyestrogens suggest that the steroid hormonal environment be considered in the examination of estrogen 2-hydroxylase and the catechol estrogen products. off

Bacillaemia and bone marrow involvement in leprosy

Fifty patients (24 new and 26 receiving specific treatment) of leprosy were investigated to study the concentration and morphological index (MI) of the lepra bacilli in skin, peripheral blood and bone marrow. The organisms were detected in 28 cases on skin slit smear examination, in 38 cases on bone marrow examination and in 38 cases on examination of smears made from buffy coat of peripheral blood. Out of 22 cases negative for the bacilli on skin slit smears, 15 had the organisms either in buffy coat or bone marrow or both. Acid fast bacilli in peripheral blood and bone marrow with skin smear negativity were mainly observed in patients with paucibacillary type of the disease and in those who were receiving treatment. Examination of buffy coat and bone marrow for presence of lepra bacilli is suggested to establish the diagnosis in doubtful cases.

Serum glycoproteins in pulmonary tuberculosis

Serum glycoprotein levels were studied in 50 patients of pulmonary tuberculosis and 25 healthy controls. Ten of the tuberculosis patients had stage I disease, 24 stage II, 9 stage III and 7 had pulmonary tuberculosis with effusion. The serum levels of protein bound hexose, protein bound hexosamine, protein bound fucose and protein bound sialic acid were significantly higher (P less than 0.001) in patients with pulmonary tuberculosis as compared to controls; the mean values being 195.6, 189.1, 16.3 and 120.8 mg/dl respectively in patients and 117.0, 84.1, 7.7 and 67.2 mg/dl respectively in controls. The levels were not influenced by age and sex of the subjects in both groups. The levels were found to increase in all the stages of pulmonary tuberculosis with a marginal difference. Treatment with antituberculosis drugs resulted in a decrease in ESR and the various fractions of serum glycoproteins at subsequent follow up, however, the mean levels did not reach those of control subjects and were not influenced by the type of therapy.

Effects of dilazep in evolving myocardial infarction in dogs: a biochemical study

Mongrel dogs of either sex with ligation of their left anterior descending coronary artery were employed for the present study to investigate the biochemical basis of the cardioprotective action of dilazep. Dilazep (0.2 mg/kg intravenous) was administered 20 minutes after coronary arterial occlusion. Ligation of the artery for 40 minutes increased the tissue lactate concentration and decreased the adenosine triphosphate molecules within the occluded bed. Dilazep decreased the lactate concentration and improved the adenosine triphosphate content of this bed significantly. Dilazep also lowered the tissue cyclic adenosine monophosphate concentration and free fatty acid extraction of the ischemic myocardium as studied 40 minutes after coronary arterial ligation. It can be inferred that less free fatty acid extraction and calcium antagonistic action of dilazep helps in restoring mitochondrial function. Furthermore, decreased tissue lactate concentration resulted after better perfusion of the occluded bed and helped in greater generation of adenosine triphosphate molecules. These favorable biochemical and metabolic changes contribute to the cardioprotective action of dilazep.

An extension of a model for first birth interval and some social factors

"A model for the time of first birth is presented under certain assumptions, which involve biological and socio-cultural factors." The model is illustrated using data from Rural Development and Population Growth--A Sample Survey, 1978, conducted in Varanasi, India, and involving some 3,514 households.

Multiaxial orthotic hip joint for squatting and cross-legged sitting with hip-knee-ankle-foot-orthosis

In view of the importance of squatting and cross-legged sitting in the activities of daily living in Asian and African countries, a multiaxial orthotic hip joint has been developed which when fitted to a Hip-Knee-Ankle-Foot-Orthosis (HKAFO) can permit the user to squat and sit cross-legged. The design consists of a modified ball and socket joint.

Antinutritional factors of chickpea and pigeonpea and their removal by processing

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.

Comparison between serum isonicotinic acid hydrazide (INH) levels and urinary sulfadimidine (sulfamethazine) acetylation as predictors of INH acetylator status

The acetylator status of 40 children with pulmonary tuberculosis was investigated by (1) sulfadimidine (SDM; sulfamethazine) acetylation test in urine and (2) estimation of isonicotinic acid hydrazide (INH) levels. The antimode was at 70% based on the frequency distribution of SDM acetylation. Children acetylating less than 70% of administered SDM were taken as slow acetylators while those with more than 70% as rapid acetylators. The serum INH antimode was at 0.85 micrograms/ml. Thus serum values less than 0.85 micrograms/ml categorised a child as rapid and those with more than 0.85 micrograms/ml as slow acetylators. The sensitivity of these two methods was similar with a correlation coefficient r = 0.64. Thus the determination of the type of acetylator by SDM acetylation test is equally reliable and technically simpler and is recommended instead of INH serum concentration.

Parasympathetic innervation of the thymus: a histochemical and immunocytochemical study

The presence of parasympathetic nerve supply to the thymus has been demonstrated by histochemical and immunocytochemical methods using antibodies against cholineacetyl transferase. Fine nerve fibres have been observed both in the thymic parenchyma and around the blood vessels. The role of the parasympathetic nerve supply to the thymus is briefly discussed.

Lymphopoiesis in the nude fetal thymus following sympathectomy

This study was carried out to examine the innervation of the nude fetal thymus during ontogeny and to see if lymphopoietic activity would occur within these thymic lobes in the absence of sympathetic neuronal input. Fetal thymic rudiments from nu/nu mice were removed and examined for galoxylic acid-induced histofluorescence to detect the catecholaminergic nerves. Some of these lobes were organ cultured for 5 to 7 days in the presence of deoxyguanosine to eliminate any existing lymphoid cells within the rudiments. Such "nonlymphoid" thymic rudiments were implanted into the anterior eye chambers of syngenic BALB/c mice (heterozygous) from which cervical sympathetic ganglia and part of the sympathetic chain had been surgically removed (right side) one week earlier. The left side was only sham operated. The thymic implants were allowed to grow for up to 21 days on both sides; they were then removed and examined by histofluorescence, immunofluorescence, and light microscopy. The results indicate for the first time that the nude fetal thymus is innervated by sympathetic nerves and that following sympathectomy the nude thymus is able to sustain lymphopoietic activity and generate lymphoid cells which have characteristics present on thymocytes during in vivo development in normal mice, such as binding to peanut agglutinin and expression of Thy-1 antigen. The relationship between the presence of sympathetic inhibitory influence and the thymic atrophy seen in the nude mice during ontogeny, is being investigated.

Sympathetic innervation of fetal mouse thymus

This study was carried out to investigate the presence of sympathetic nerve fibers in the developing thymus. Thymic rudiments from 13 days of gestation up to birth and adult thymuses were examined by histofluorescence microscopy to detect the presence of these nerve fibers during ontogeny. Sympathetic nerve fibers were first visible around day 17 of gestation and increased in density and distribution by the time of birth and in the adult thymus. The appearance of immunoreactive cells about the same time as the presence of nerve fibers in the thymic rudiments has been discussed in light of a regulatory role for the sympathetic neuronal input on the maturation of thymocytes during ontogeny.