Desensitization of human breast-cancer cells by interferon-alpha

Continuous exposure of human breast cancer cells, MCF-7, to interferon-alpha (IFN) induces a state.of non-responsiveness termed as desensitization. mRNA 561 is transiently induced by IFN-alpha in MCF-7 cells, peak cytoplasmic levels are reached by six to twelve hours; the mRNA level declines steadily and is reduced to uninduced levels by forty eight hours. Induction of mRNA 561 was used as an index of responsiveness of cells to IFN-alpha and desensitization was characterized in MCF-7 cells and in MCF-7 cells transfected by the v-H-ras oncogene (MCF-7ras). The kinetics and degree of IFN-mediated induction of mRNA 561 was comparable in both the cell lines. Desensitization was observed in MCF-7 cells and not in MCF-7ras. It was a reversible event, requiring de novo protein synthesis as inclusion of cycloheximide inhibited desensitization. The cellular elements that mediate such a phenomena are elicited by IFNs during the initial phases of IFN action and may be polypeptides. The refractory period, the time after which MCF-7 cells become responsive, was determined to be five days. In conclusion, we demonstrate the use of mRNA 561 induction in evaluating desensitization. Inhibition of protein synthesis or transfection with ras blocks desensitization in MCF-7 cells.     

Effects of L-ascorbic acid supplementation on dieldrin toxicity in rats

Chronic dieldrin administration to rats (5 mg/kg/day) produced pathological changes in liver and kidney tissues. Dieldrin treated rats showed high levels of liver ascorbic acid and increased activities of inorganic pyrophosphatase in brain and glucose-6-phosphatase in liver. The activities of Mg²⁺-ATPase in liver and acetylcholinesterase in brain were decreased under toxic doses of dieldrin. L-Ascorbic acid supplements in treated animals could partially prevent the pathological alterations, as observed histologically in liver and kidney tissues. Administration of this vitamin could also prevent alterations in some enzyme activities produced by toxic dieldrin doses.     

Study of lymphatic metastatic patterns in gastric carcinoma according to tumor location

A total of 226 cases of advanced gastric cancer which occupied only one third of the stomach were analyzed in order to clarify whether and how lymphatic spread differed according to the tumor location and gross type of tumor. Out of the 226 patients, 45 cases had tumor in the upper third, 74 cases had it in the middle third, and 107 cases had it in the lower third of the stomach. The incidence of lymph node metastasis was found to be much higher for the tumors located in the lesser curvature (51.6%), greater curvature and posterior wall (54.4%), as compared to the tumors located in the anterior wall (28.0%). The tumors located in the upper third of the stomach did not show any metastasis in the N3 node, while the tumors located in the lower third of the stomach did not show any metastasis in the left cardial nodes, short gastric nodes, and the nodes along the left gastroepiploic vessels. Similarly, the tumors from the middle third of the stomach did not invade the left cardial nodes.     

Identification of a novel pulmonary oedema producing toxin from Indian red scorpion (Mesobuthus tamulus) venom.

The experiments were conducted to identify the toxin that produces pulmonary oedema in Mesobuthus tamulus (BT) envenomed animals. Crude BT venom was subjected to Sephadex gel filtration (G-75) and the fractions were screened for optical density (OD), neurotoxicity (prolongation of compound action potential in frog sciatic nerve) and lethality. All these parameters exhibited a peak between 54-94 ml eluates. Fractions of this peak were pooled (SP) and loaded on to carboxymethyl cellulose column. The column was then eluted with increasing buffer concentrations at constant pH and temperature. Eluates were screened for neurotoxicity and OD. Four peaks of neurotoxic activity (T1-T4) were detected. T2 and T3 were lethal whereas T1 and T4 were non-lethal. T2 exhibited mainly neurotoxicity and failed to augment phenyldiguanide (PDG)-induced reflex response or to produce pulmonary oedema. T3 was having minimal neurotoxic actions but augmented PDG-reflex and produced pulmonary oedema. The effects of T3 persisted even after dialysis with 8 kDa cut-off filter but not those of T2. The T3 effects resembled toxic manifestations of BT venom and were blocked by aprotinin pre-treatment. T3 demonstrated a band at approximately 100 kDa in SDS-PAGE. The results demonstrate the presence of a lethal, high molecular weight, pulmonary oedema producing toxin in BT venom.     

Nasal mucociliary clearance in health and disease

“Standard saccharine test is used to detect nasal mucociliary clearance time in healthy individuals both adults and children. The length of the nose was measured radiologically and with the help of a soft malleable rubber catheter. For healthy individuals, mean nasal mucociliary clearance lime is 8.2 minutes in children and 9.5 minutes in adults. The mean nasal mucociliary clearance rates were 11.1 mm/min for children and 12.7 mm/min for adults. Deviated nasal septum, chronic sinusitis, allergic rhinitis, atrophic rhinitis, chronic smokers and patients with recent nasal packings were taken as diseased conditions in adults, whereas children with adenoid hyperplasia were taken for the study. In all of these, nasal mucociliary clearance was significantly prolonged.”     

A Current Review of Cypermethrin-Induced Neurotoxicity and Nigrostriatal Dopaminergic Neurodegeneration

Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed.     

Microbial keratitis following vegetative matter injury

The purpose of the present study was to analyze the microbiological profile of cases of keratitis following trauma with vegetative matter in a tertiary care center. A retrospective review of the medical records of 49 patients with keratitis following vegetative matter injury over a 3-month period was performed. All patients underwent corneal scraping for smears and inoculation onto various culture media. The microbiological profile was based on the smear and culture reports. For patients who were culture-negative, outcome after standard empirical antibacterial therapy as per hospital protocol was analyzed. Thirteen patients with corneal ulcers had fungal etiology, eight had bacterial etiology, and two had protozoal etiology, while 13 patients were polymicrobial and 13 were culture-negative. Polymicrobial infections were mainly bacterial (eight cases), and the remaining five cases had coexistent fungal and bacterial etiology. The treatment was directed to the specific organism and patients improved with medical or surgical therapy. Only a third of culture-negative cases showed fungal etiology on biopsy or histopathology after keratoplasty while a third showed improvement with therapy. Corneal infections following vegetative matter trauma show a varied etiological profile; however, bacterial and polymicrobial infections are more prevalent. Empirical anti-fungal therapy, as commonly practiced, must be avoided in cases with vegetative matter injury.     

Bleomycin sclerotherapy in lymphangiomas of the head and neck region: a prospective study

Intralesional sclerotherapy for lymphatic malformations (LMs) has become a modality of choice because of the high morbidity and recurrence rates with surgical excision. Traditionally, the macrocystic variant has shown good results with sclerotherapy. This prospective study was performed to evaluate the role of bleomycin sclerotherapy in the management of different radiological variants of LM. A total of 142 patients were included in this study. The lesions were classified as macrocystic, microcystic, or mixed LMs on the basis of ultrasonography. All patients were managed by intralesional injection of bleomycin and were recalled after 4 weeks for evaluation. Colour photographs of the patients were taken before the onset of treatment and at each monthly visit, and were utilized to assess the response. Following the second, third, and fourth doses, the response was better in patients with the macrocystic variant than in those with the other two variants. However, after the completion of six doses, 80.3% of patients with the macrocystic variant, 67.4% with the microcystic variant, and 71.4% with the mixed type had a complete response. There was no difference in the overall response between the three types (P = 0.28). Oedema, erythema, and local induration with fever were the most common adverse effects and were more common in younger children.