Revisiting the pestilence of Helicobacter pylori: insights into geographical genomics and pathogen evolution.

Helicobacter pylori causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. It is believed that H. pylori infects over 50% of the worlds' population. However, only a small subset of infected people experience H. pylori-associated illnesses. Associations with disease-specific factors remain enigmatic. The contribution of comparative genomics to our understanding of the genome organisation and diversity of H. pylori is exemplified herein. The discovery of the cag pathogenicity island has revolutionised our understanding of the molecular pathogenesis of gastroduodenal ulcers. Another type IV secretion system, the comB gene cluster, provides a novel transformation system. Identification of this cluster has boosted our perception of horizontal gene transfer and gene mosaicism in H. pylori as a result of natural competence. Recent discovery of a third type IV secretion system called tfs3 encoding cluster in the so called plasticity zone of the H. pylori has gained significant attention, although its role is not clear. Study of the evolution of polymorphisms and sequence variation in H. pylori populations on a global basis is contributing to understanding of the history of human population migration and co-evolution of this pathogen with its human host. Possible symbiotic relationships were debated since the discovery of this pathogen. The debate has been further intensified as recent studies have posed the intriguing possibility that H. pylori infection may be advantageous in some humans. This analogy is based on increased incidence of diseases like gastro-oesophageal reflux disease (GERD), Barrett's oesophagus and adenocarcinoma of the oesophagus following H. pylori eradication in some patients.     

An unusual orbito-cranial foreign body.

The rarity of orbito-cranial gun shot injury in both war and civilian practice has been reported. In a large series of 351 missile head injuries in the Vietnam war, orbital penetration was noted in 0.6% cases only. Review of literature shows that orbital injury was ipsilateral to the cerebral injury in most reported cases. We have previously reported a rare case of left parieto-occipital lobe injury due to gun shot wound of the contralateral (right) orbit. The case reported here sustained a bullet injury to the left frontal bone but the missile was located below the contralateral (right) optic canal. The rarity of the case prompted this report.     

Arthroscopic resection of chondroblastoma of the knee.

We present a case of chondroblastoma of the upper tibia treated by complete arthroscopic excision. The diagnostic difficulties raised by the case are discussed. This method of treatment has not, to our knowledge, been reported in the literature.     

Epibatidine binding sites and activity in the spinal cord

Epibatidine has been shown to be the most potent nicotinic agonist in several neuronal nicotinic receptor preparations. Similar to other nicotinic agonists, intrathecal (−)-epibatidine elicits dose-dependent increases in pressor, heart rate and pain responses in rats, as well as an increase in latency to withdraw from a noxious thermal stimulus. The latter response requires higher doses and is of shorter duration, suggesting interaction with multiple subtypes of spinal nicotinic receptors. In the present study, we relate the binding properties of (±)-[³H]epibatidine in spinal cord membrane preparations to the cardiovascular and behavioral responses. Unlike (−)-[³H]cytisine or (−)-[³H]nicotine, (±)-[³H]epibatidine reveals two sites; the ratio of high affinity to low affinity sites is 2:1. The rank ordering of potencies of the nicotinic agonists in displacing (±)-[³H]epibatidine binding from spinal cord membranes correlates with the potencies in eliciting cardiovascular and behavioral responses upon spinal administration. The nicotinic receptor antagonists, α-lobeline, dihydro-β-erythroidine and methyllycaconitine, also displayed similar rank ordering of potencies in displacing (±)-[³H]epibatidine, (−)-[³H]cytisine or (−)-[³H]nicotine binding to spinal nicotinic receptors. Virtually all the nicotinic analogs exhibited a Hill coefficient of less than one in competing with (±)-[³H]epibatidine to spinal cord membranes indicating their interaction with at least two classes of binding sites. Intrathecal (−)-epibatidine, in addition to eliciting an initial and subsequently a sustained pressor and tachycardic response, also exhibited a transient intervening bradycardia which coincided temporally with the duration of the analgesia. Repeated administration of (−)-epibatidine desensitized its responses as well as the cardiovascular and behavioral responses to spinal nicotine and cytisine. Intrathecal α-lobeline showed selectivity for blocking the analgesic response, whereas methyllycaconitine exhibited selectivity for the pressor and irritation responses. The NMDA receptor antagonist, AP-5, inhibited the pressor, tachycardic and irritation responses elicited by intrathecal (−)-epibatidine, confirming a role for spinal excitatory amino acids released by the nicotinic agonist. © 1997 Elsevier Science B.V. All rights reserved.     

Suppression by serum of immunoreactivity to a common tumour antigen in cancer patients

Leucocytes from 4 cancer patients showed cellular reactivity in the leucocyte adherence inhibition (LAI) assay in the presence of the synthetic encephalitogenic peptide of human myelin basic protein. All patients exhibited reactivity at a peptide concentration of 500 ng/ml. Leucocytes from 4 non-cancer patients failed to react. Suppression of LAI was detected in all 4 cancer patients by adding their serum to reactive mixtures containing peptide and autologous leucocytes. Each serum was subjected to column chromatography on Sephacryl S-200 to determine the molecular weight distribution of suppressive (blocking) factors. The greatest suppression was found in all cases within the range 90-155 kdalton.     

A randomized, single blind comparative trial of norethindrone enanthate and depo-medroxyprogesterone acetate in Bangladesh

A randomized, single blind comparative trial of norethindrone enanthate (NET-ENT) and depo-medroxyprogesterone acetate (DMPA) was conducted in the Model Clinic, Decca, Bangladesh, to determine if there were differences in reported side effects, reasons for discontinuation and discontinuation rates of these two injectables. On all follow-up visits the proportion of women reporting no bleeding (amenorrhea) was higher for the DMPA clients compared to the NET-ENT clients. Concurrent with these findings, the proportion of women reporting irregular bleeding was consistently higher for the NET-ENT clients. Concurrent with these findings, the proportion of women reporting irregular bleeding was consistently higher for the NET-ENT clients compared to those receiving DMPA. By the fourth injection, less than 15% of the clients in both drug groups still reported having regular cyclic bleeding (4 of the 26 DMPA clients and 4 of the 28 NET-ENT clients). Five of the 133 women on DMPA and 6 of the 106 women on NET-ENT became pregnant while using the injectables. At the end of one year of follow-up, 14 of the 133 DMPA and 14 of the 106 NET-ENT clients were still continuing (came back for a fifth injection).