Polymyxins: Antimicrobial susceptibility concerns and therapeutic options.

The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.

Neurogenic appendicopathy--role of enterochromaffin cells in its pathogenesis.

One hundred cases of neurogenic appendicopathy were histochemically studied for schwann cells and enterochromaffin cells. The early phase, labelled as neuro-appendicopathy (29 cases) showed minimum to moderate number of extraepithelial enterochromaffin cells without neurogenous hyperplasia. In 53 cases, there was intra and submucosal neural hyperplasia with increase in the extraepithelial enterochromaffin cells, representing the active phase. The late phase known as obliterative neurogenic appendicopathy, showed extraepithelial enterochromaffin cells and schwann cell proliferation of variable grades (18 cases). The origin of extraepithelial enterochromaffin cells is related to proliferating nerve plexus, rather than epithelial enterochromaffin cells.

Connective tissue stromal changes in tumours and tumour-like lesions of the breast.

Between June 1994 and December 1995, one hundred and fifteen tumours and tumour-like lesions of the breast were studied in the Department of Pathology, Kasturba Medical College, Mangalore. Neoplasms constituted 80.9% and tumour like lesions accounted for 19.13%. Among the tumours, 51.6% were benign and 48.4% were malignant. Tumour-like lesions included the entire spectrum of fibrocystic disease. Tumours were common between 2nd and 8th decades while tumour-like lesions were uncommon above 6th decade. Whereas benign tumours exhibited ground substance, collagen and reticulin fibres in varying amounts, tumour-like lesions and carcinoma showed more of collagen fibres and less of ground substance. Elastosis and lymphoplasmacytic infiltrate were prominent features in carcinomas rather than in benign lesions.

Distribution of mast cells in the axillary lymph nodes of breast cancer patients.

Fifty mastectomy specimens of carcinoma breast were studied for pattern of mast cell distribution in their axillary lymph nodes. When all axillary nodes were free of tumour, the mean mast cell count was 35.75/sq mm. In the metastatic node the mast cell count was inversely proportional to the amount of metastatic tumour. The mast cell number decreased (25.64/sq mm) as the metastasis developed in any of the enlarged axillary nodes. Their count diminished further (23.55/sq mm) as the amount of metastatic tumour increased in individual nodes and when tumour involved all enlarged nodes. Mean mast cell count was lowest (10.50/sq mm) in metaplastic carcinoma. The mast cells in metastatic nodes were found mainly at the edges of tumour deposits.

Extragonadal germ cell tumours in Mangalore with review of the literature.

In the present study 32 extragonadal tumours, reported in 38 years (1956 to 1994) from the department of pathology, Kasturba Medical College, Mangalore were analysed. These were seen predominantly in infants and children mainly affecting females. The commonest sites of these tumours were sacrococcygeal region (46.88%) followed by retroperitoneum and mediastinum. The rarest sites were mesentery, fallopian tube and suprasellar region in the cranial cavity. Histologically 27 out of 32 cases were teratomas, 75% of which were benign.