Modulation of humoral and cell-mediated immune responses by Azadirachta indica (Neem) in mice

The effects of A. indica (AI, Neem) were evaluated on tests of humoral and cell-mediated immune responses after 3 weeks of oral AI (leaf extract) treatment in ovalbumin immunized mice. At the dose levels tested, AI (10, 30 or 100 mg/kg), had no appreciable influence on different organ (liver, spleen, thymus)/body weight indices, when compared to controls. In tests for humoral immune responses, AI (100 mg/kg) treated mice had higher (1) IgM and IgG levels, and (b) anti-ovalbumin antibody titres, when compared to the vehicle treated group. In tests for cell-mediated immune responses, there was an enhancement (%) of (a) macrophage migration inhibition, and (b) footpad thickness after AI (100 mg/kg) treatment. These results are discussed in light of the possible immunopotentiating effects of AI.

The effects of an RNA synthesis inhibitor on the survival and regeneration of rat motoneurones injured at birth

This preliminary study aimed to test the proposal that neuronal death is triggered by expression of specific genes. In rat pups, the sciatic nerve was injured unilaterally on the first day after birth and actinomycin D, an RNA synthesis inhibitor, was administered 3 days later in a lower and higher dose to rat pups just prior to onset of motoneurone death induced by the lesion. Four weeks later, sciatic motoneurones from operated and contralateral pools were counted and their size measured. Significantly fewer motoneurones (16.7% +/- 2.9 SD) survived when the animals were treated with a lower dose of the inhibitor compared to saline treated controls (36.6% +/- 12.7 SD). Experiments recording tension generated in soleus muscle in response to sciatic nerve stimulation, at different ages following nerve crush, suggested that the treatment with the RNA synthesis inhibitor may have delayed regeneration of motor axons back to the muscle. However, survival of motoneurones after treatment with the higher dose did not differ significantly from controls (27.5% +/- 1.3 SD). Nevertheless, the higher dose significantly reduced growth of motoneurones after 4 weeks. Therefore, the higher dose, although impeding normal development of motoneurones, is less neurotoxic than a lower dose. This suggests that a balancing of conflicting effects may have occurred. The neurodegenerative effects of delayed reinnervation induced by RNA synthesis inhibition may be balanced by some neuroprotective effects at a higher dose. More extensive studies are required to validate these pilot findings.

Antinociceptive action of Azadirachta indica (neem) in mice: possible mechanisms involved

Azadirachta indica (AI, Neem) was tested for analgesic potency in experimental pain models in mice. In the glacial acetic acid (GAA) induced writhing test, AI (10, 30 and 100 mg/kg) dose-dependently reduced both the incidence and the number of writhes. Similarly, AI, at the dose levels tested, also enhanced tail withdrawal latencies in the tail-flick test for nociception. In the interaction studies, pretreatment with the opioid antagonist, naloxone (1 mg/kg) and the central noradrenaline depleter, DSP-4 (50 mg/kg) attenuated AI analgesia by differential degrees in both experimental models, whereas, the serotonin synthesis inhibitor, PCPA (300 mg/kg) potentiated the same. These results suggest that both central and peripheral mechanisms and complex neural pathways, opioid and non-opioid, may be involved in AI induced analgesia.

Corticosteroid-induced asthma: a manifestation of limited hyperinfection syndrome due to Strongyloides stercoralis

Inadequate therapeutic response to parenteral corticosteroids in patients with acute bronchial asthma is infrequent. We report four patients whose bronchial asthma symptoms worsened after treatment with parenteral corticosteroids. All had larvae of Strongyloides stercoralis in the stool. The new attack or the exacerbation of asthma appeared to be precipitated by systemic corticosteroid administration. The paradoxic therapeutic response of asthma to glucocorticoides was the major pulmonary manifestation of Strongyloides superinfection; there was no evidence of other organ involvement. Individuals with new onset of bronchial asthma or worsening of asthmatic episodes concurrent with the use of systemic corticosteroids should have thorough investigation for possible superinfection due to Strongyloides stercoralis. This is particularly important for patients who have resided in areas where intestinal helminthic infections are endemic. Discontinuance of steroid therapy or reduction in dosage of parenteral steroids appears necessary. Treatment with thiabendazole appears to be effective in patients with limited hyperinfection syndrome.

Fat and oil inhibit phosphine release from aluminium phosphide--its clinical implication

Poisoning by suicidal or accidental ingestion of aluminium phosphide (AlP) is a frequent medical emergency seen all over the world. AlP, a grain fumigant and rodenticide, on exposure to moisture, liberates highly toxic gas, phosphine. The rapidly inhibits mitochondrial respiration and has cytotoxic action. No specific antidote is known against it till date and prognosis depends much on dose and time lag between AlP ingestion and the stomach wash in the hospital (critical period). Physicochemical properties of AlP and nonmiscibility of fat and water promoted us to study the effect of different fats and oils as possible antidotes to inhibit phosphine liberation. In vitro experiments revealed that vegetable oils and liquid paraffin were much more effective than butter and ghee in inhibiting release of phosphine from AlP. These findings may have significant clinical implication.

Role of dopaminergic mechanisms in the regulation of stress responses in experimental animals

The effects of some dopaminergic agents were evaluated on stress responses in normal and immunized experimental animals. Restraint stress (RS) consistently induced gastric mucosal lesions and elevated plasma corticosterone in rats. Pretreatment with alpha-methyltyrosine (alpha-MT), haloperidol, or sulpiride aggravated both responses, whereas bromocriptine attenuated them. In rats immunized with sheep red blood cells (SRBCs), RS prevented the booster-induced rise in anti-SRBC antibody titre. This response was further suppressed by alpha-MT, haloperidol, or sulpiride pretreatment, whereas bromocriptine potentiated the humoral immune response. In mice immunized with SRBCs, antigen challenge-induced increase in footpad thickness was inhibited by RS. Similar inhibitions in this response were also seen after alpha-MT or haloperidol treatment. The results are discussed in light of complex dopaminergic mechanisms in the regulation of visceral, endocrinological, and immune responses during stress.

Microdissected double-minute DNA detects variable patterns of chromosomal localizations and multiple abundantly expressed transcripts in normal and leukemic cells

Double-minute (dm) chromosomes are cytogenetically resolvable DNA amplification-mediating acentric extrachromosomal structures that are commonly seen in primary tumors, tumor cell lines, and drug-resistant cells grown in vitro. Selective isolation of dm DNAs with standard molecular biological techniques is difficult, and thus, detailed studies to elucidate their structure, site of chromosomal origin, and chromosomal reintegration patterns have been limited. In those instances in which a gene has been localized on dms, characterization of the remainder of the DNA, which far exceeds the size of the gene identified, has remained inconclusive, dms seen in the acute myeloid leukemia cell line HL-60 have been shown to harbor the c-myc protooncogene. In this paper, we report the successful isolation of the dm-specific DNAs from these cells by the microdissection/polymerase chain reaction technique and demonstrate that the dm DNAs derived from a single discrete normal chromosome segment 8q24.1-q24.2 reintegrate at various specific locations in the leukemic cells. The microdissected dm DNA detects multiple abundantly expressed transcripts distinct from c-myc mRNA on Northern blots. By devising a "transcript selection" strategy, we cloned the partial genomic sequence of a gene from the microdissected DNA that encodes two of these RNAs. This strategy will be generally applicable for rapid cloning of unknown amplified genes harbored on dms. With DNA from 20 microdissected dms, we constructed a genomic library of about 20,000 recombinant microclones with an average insert size of about 450 bp.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchiolitis obliterans organizing pneumonia associated with massive L-tryptophan ingestion

A 51-year-old woman developed acute febrile illness with respiratory failure following intake of L-tryptophan. An open lung biopsy specimen established the histopathologic nature of the lung lesion as bronchiolitis obliterans organizing pneumonia (BOOP). There was no evidence of other known causes usually associated with BOOP. Her condition improved with corticosteroid therapy. The entity of BOOP now should be added to the growing list of illnesses associated with the use of L-tryptophan.

The amygdaloid complex, corticotropin releasing factor and stress-induced gastric ulcerogenesis in rats

The amygdaloid complex and corticotropin releasing factor (CRF) are both important in stress reactions and we thus evaluated the effects of intra-amygdalar CRF on stress ulceration in rats. Bilateral micro-applications of CRF (0.05, 0.5 or 5.0 micrograms) into the central amygdala (CEA) attenuated cold restraint-induced gastric mucosal lesions in a dose-related manner. Similar gastric cytoprotective effects were seen with intra-CEA noradrenaline (NA; 3.0 micrograms), whereas the NA neurotoxin, DSP-4 (25 micrograms), or the beta-adrenoceptor antagonist, propranolol (1 microgram), aggravated stress ulcer pathology. Intra-CEA pretreatment with DSP-4 or propranolol clearly reversed the ulceroprotective effects of CRF during stress. These results indicate that the CEA is a neural substrate for CRF effects, and CRF-NA interactions in this limbic area are crucial for the regulation of stress ulcerogenesis.

Teaching humanistic behavior: humanities study in the internal medicine residency

Training in humanism is required in internal medicine residency programs, but teaching and evaluating humanism is difficult. Our program integrates the study of humanities into residency training for professional and personal development; betterment of communication skills; and understanding of ethics.