Neuropathology of genetically engineered mice: consensus report and recommendations from an international forum

The Mouse Models of Cancer Consortium of the NCI sponsored a meeting of neuropathologists and veterinary pathologists in New York City in November of 2000. A rapidly growing number of genetically engineered mice (GEM) predisposed to tumors of the nervous system have led to a concomitant need for neuropathological evaluation and validation of these models. A panel of 13 pathologists reviewed material representing most of the available published and unpublished GEM models of medulloblastoma, primitive neuroectodermal tumor, astrocytoma, oligodendroglioma, mixed glioma, and tumors of the peripheral nerve. The GEM tumors were found to have many similarities and some distinct differences with respect to human disease. After review of the biology and pathology for all models presented, participants were split into groups reflective of clinical expertise in human pathology, tumor biology, neuroimaging, or treatment/intervention. Recommendations were made detailing an extensive and complete neuropathological characterization of animals. Importance was placed on including information on strains, tumor clonality, and examination for genetic mutation or altered gene expression characteristics of the corresponding human malignancy. Specific proposals were made to incorporate GEM models in emerging neuroradiological modalities. Recommendations were also made for preclinical validation of these models in cancer therapeutics, and for incorporation of surrogate markers of tumor burden to facilitate preclinical evaluation of new therapies.     

Study of sudden cardiac deaths in young athletes

Sudden cardiac deaths in athletes are usually due to underlying cardiovascular disease. The final pathway is usually ventricular fibrillation following hypertrophic cardiomyopathy and coronary artery anomalies in young persons below the age of 30 years. Sudden cardiac death in young is rare but remains as a source of concern. A postmortem study was conducted to ascertain the cardiac causes of sudden death in persons below the age group 30 years following exercise in games or otherwise. Out of 15 cases in autopsy finding, hypertrophic cardiomyopathy (n=7) was the commonest cause followed by coronary artery anomalies (n=4). Sudden unexpected death is a source of concern and careful screening of history and physical examination for potential athletes should identify majority of people at risk.     

Paratesticular rhabdomyosarcomas and leiomyosarcomas: a clinicopathological review.

One case of embryonal paratesticular sarcoma and 2 cases of leiomyosarcomas are reported. The 13-year-old boy with embryonal sarcoma is well after an orchiectomy and high ligation of the spermatic cord followed by radiotherapy and chemotherapy. A 66-year-old man has been doing well after orchiectomy and hemiscrotectomy for a paratesticular leiomyosarcoma. The third patient had a highly pleomorphic leiomyosarcoma and died 2 months postoperatively. The clinical and histological diagnosis of paratesticular rhabdomyosarcomas and leiomyosarcomas is reviewed and the various therapeutic approaches to these neoplasms are discussed. Retroperitoneal lymph node dissection, radiotherapy and chemotherapy are important adjuncts to orchiectomy in the management of rhabdomyosarcomas. On the contrary, retroperitoneal lymph node dissection and radiotherapy are not indicated in leiomyosarcomas, since these neoplasms tend to metastasize by the hematogenous route and are radioresistant. At the present time we are unable to evaluate chemotherapy in the management of paratesticular leiomyosarcomas.     

Differential methylation of genes that regulate cytokine signaling in lymphoid and hematopoietic tumors

The perturbations of the cytokine signaling pathway play an important role in lymphoid/hematopoietic tumors. Aberrant promoter methylation is the major mechanism of gene silencing in tumors. We examined 150 lymphoid/hematopoietic tumors or potential premalignant specimens, 55 control specimens and 12 EBV-transformed B lymphoblastoid cultures and 10 lymphoma/leukemia (L/L) or multiple myeloma (MM) cell lines for the methylation (and, in cell lines, of the expression status) of three genes involved in the cytokine signaling pathway. The genes were: SHP1, a protein tyrosine phosphatase; SYK, a protein kinase; and SOCS1, a suppressor of cytokine signaling. Our major findings were: (1) one or more of the three genes was frequently methylated in L/L and MM cell lines and there was good concordance (90-100%) between methylation and loss of gene expression; (2) treatment of L/L cell lines with a demethylating agent resulted in re-expression of SHP1 protein and downregulation of phosphorylated STAT3 in L/L cell lines; (3) all 55 control specimens and the lymphoblastoid cultures were negative for methylation of the three genes; (4) non-Hodgkin's lymphomas (100%), and leukemias (94%) had almost universal methylation of SHP1 and relatively less frequent (<30%) methylation of SOCS1 and SYK; (5) MM and monoclonal gammopathy of unknown significance (MGUS) had infrequent methylation of SHP1 (<20%), and occasional methylation of SOCS1 and SYK; and (6) comparable methylation frequencies for SOCS1 were observed in MM and MGUS, suggesting that SOCS1 methylation is an early event in MM pathogenesis. At least one gene was methylated in 119 of 130 (93%) of the malignant and 12 of 20 (60%) of the MGUS samples. Our findings demonstrate that the perturbations of cytokine signaling via silencing of these three genes are almost universal in lymphoid/hematopoietic tumors but the patterns of gene methylated for L/L and plasma cell dyscrasias are different.     

RAPD & FINS (mitochondrial 16s rRNA gene sequence) in analysis of food contamination: detection of food poisoning by Lizard

In poisoning, detection of the nature of causative agent is important for management of trauma and forensic investigation. Most of the methods in clinical toxicology are developed for detection of toxins and poisons. A random amplified polymorphic DNA (RAPD)-based method has been described for detection of species of animal from its morphologically unrecognizable fragments, recovered from food substances, consumption of which caused even death. Pre-mixed RAPD reaction beads and six RAPD primers were used in polymerase chain reaction analysis. Among six RAPD primers used, any one of them was sufficient in resolving this practical forensic situation. To enhance the probability values for matching in the present study of fixing identity of an animal, six set of market available RAPD primers were used. This is the first report of a forensic application of RAPD DNA typing in identification of charred skeleton remnants of Lizard species in food material. Furthermore unique amplicons were generated for different reptilian species, which can be used as species specific markers for species identification in forensic situation, however, no variations among individuals of same species were observed.     

Effect of chitosan on lipid levels when administered concurrently with atorvastatin--a placebo controlled study

In a placebo controlled trialthe lipid lowering effects of chitosan, a unique dietary fibre, was assessed when given along with atorvastatin 10 mg in patients with chronic coronary heart disease. Altogether 100 patients were studied. They were randomly allocated in two groups of 50 patients each. Patients of group A received atorvastatin 10 mg before dinner plus 2 g/day chitosan in two divided doses. The groupB patients received atorvastatin 10 mg plus placebo. Patients were followed up for a period of 6 weeks. There was significant reduction in mean body weight in group A patients (3.14% versus 1,29% of body weight, p<0.05). There was also a significant rise in HDL cholesterol value (3.8% versus 1.07%, p=0.02) in group A patients. However, there was no significant reduction in the mean values of total cholesterol, LDL cholesterol and triglyceride in the two groups, although group A patients showed marginally lower values.     

RISUG (reversible inhibition of sperm under guidance)--an antimicrobial as male vas deferens implant for HIV free semen

HIV transmission from the male to the female is a major health problem. A hypothesis proposing an intra vas deferens implant of an antimicrobial compound to prevent the infection spread is presented. Mechanisms of action for the inhibition could include inactivating HIV in sperms passing through the vas deferens; drug release from the implant to destroy HIV entering into semen from genital structures distal to the vas deferens; and sperm acrosome released hyaluronidase mediated reabsorption of HIV. A subcomponent of the implant flowing along sperm pathway may have a role in reducing the entry of HIV from a positive female into penile tissue. A new drug RISUG (reversible inhibition of sperm under guidance) presently undergoing clinical trials for its contraceptive effect in the male (because it disrupts the sperm acrosome by an electrical charge and pH lowering effects) has also antimicrobial action. The drug being a combination of styrene maleic anhydride (SMA) and dimethyl sulfoxide (DMSO) on being injected into the lumen of the vas deferens produces styrene maleic acid thereby lowering pH; induces electrochemical action leading to a stable electrical charge generation; releases mandelic acid; and induces acrosome reaction in sperms with consequent release of hyaluronidase and sperm inactivation. Moreover, one time administration into the lumen of the vas gives long term action. All these phenomena very well match with the needs for HIV clearance of semen and hence RISUG is here proposed as a possible candidate material for the HIV inhibiting vas deferens implant when delivered in below contraceptive threshold dosage. For experimental validation, after obtaining data on the semen HIV load under control conditions in the HIV positive males inducted into the study, 30 mg of SMA in 120 microl of DMSO (contraceptive dose being 60 mg SMA+120 microl DMSO) is to be injected into vasa deferens bilaterally. Thereafter at intervals of one month the viral load needs to be determined in semen obtained either by masturbation or in lubricant free condom at intercourse - the method of collection remaining the same throughout for a particular subject. A significant reduction in the semen viral load following RISUG administration will validate the hypothesis. Speculated reduced female to male HIV transmission is more difficult to test. Nonspecific indications will come from a population study of the incidence of RISUG treated men becoming HIV positive as compared to that in the general population.     

Intraoperative hyperglycemia and perioperative outcomes in cardiac surgery patients

OBJECTIVE: To estimate the magnitude of association between intraoperative hyperglycemia and perioperative outcomes in patients who underwent cardiac surgery. PATIENTS AND METHODS: We conducted a retrospective observational study of consecutive adult patients who underwent cardiac surgery between June 10, 2002, and August 30, 2002, at the Mayo Clinic, a tertiary care center in Rochester, Minn. The primary independent variable was the mean intraoperative glucose concentration. The primary end point was a composite of death and infectious (sternal wound, urinary tract, sepsis), neurologic (stroke, coma, delirium), renal (acute renal failure), cardiac (new-onset atrial fibrillation, heart block, cardiac arrest), and pulmonary (prolonged pulmonary ventilation, pneumonia) complications developing within 30 days after cardiac surgery. RESULTS: Among 409 patients who underwent cardiac surgery, those experiencing a primary end point were more likely to be male and older, have diabetes mellitus, undergo coronary artery bypass grafting, and receive insulin during surgery (P< or =.05 for all comparisons). Atrial fibrillation (n=105), prolonged pulmonary ventilation (n=53), delirium (n=22), and urinary tract infection (n=16) were the most common complications. The initial, mean, and maximal intraoperative glucose concentrations were significantly higher in patients experiencing the primary end point (P<.01 for all comparisons). In multivariable analyses, mean and maximal glucose levels remained significantly associated with outcomes after adjusting for potentially confounding variables, including postoperative glucose concentration. Logistic regression analyses indicated that a 20-mg/dL increase in the mean intraoperative glucose level was associated with an increase of more than 30% in outcomes (adjusted odds ratio, 1.34; 95% confidence Interval, 1.10-1.62). CONCLUSION: Intraoperative hyperglycemia is an independent risk factor for complications, including death, after cardiac surgery.     

Design for positive pressure respirators

This study deals with the design of a positive pressure respirator using a first order non-linear lung model. The non-linearities considered are non-linear airway resistance, effect of hysteresis and non-constant dead space. The analysis has been carried out using three different waveforms,viz., rectangular, sine and ramp. It is shown that the last two waveforms result in longer inspiratory periods making the actual respirators more reliable in operation.