Host response and tumour biological behaviour in the two histological types of gastric carcinoma

It appears that there is validity in categorizing gastric carcinoma into two histologic types, intestinal and diffuse. The local host tissue response in 92.5% of cases of the intestinal type of gastric carcinoma was of an exudative nature. Diffuse gastric carcinoma in 70% of cases incited a dense productive fibrosis. Pools of mucin and large number of 'signet-ring' cells were mostly encountered in the intestinal type of carcinoma. Applying Dukes' parameters the tumour was found to be more than three times more invasive in cases of diffuse carcinoma. The prognostic bearing of the two histologic types, different host tissue response, behaviour of the tumour in terms of mucous production and local extension are discussed and it is suggested that diffuse gastric carcinoma carries a worse prognosis than the intestinal type. Study of a larger series of cases and longer follow-up with controlled treatment is essential to confirm this assessment.     

Effect of Varying Atrial Sensitivity, AV Interval, and Detection Algorithm on Automatic Mode Switching

Automatic mode switching (AMS) is absolutely dependent on atrial tachyarrhythmia detection. The effects of programming several features that could influence tachyarrhythmia detection were assessed in 18 patients (six women; mean age 64 years) with pacemakers having AMS capability. The atrial electrogram amplitude in sinus rhythm at implant (SR-EGM), last measured atrial sensing threshold prior to tachycardia (A-SENS), and atrial sensing threshold for effective AMS during atrial tachyarrhythmia (AMS-SENS) were obtained. Additionally, ten patients had AV intervals increased from 60 to 200 ms, while seven patients had detection algorithms made more stringent from 5 beats at 150 beats/min to 11 beats at 200 beats/min to assess their effects on AMS efficacy. Results: Sensitivities: Mean SR-EGM = 3.55 mV; mean A-SENS = 2.06 mV; and mean AMS-SENS = 1.46 mV. Fourteen patients developed atrial fibrillation and four atrial flutter. Thirteen of 14 patients who developed atrial fibrillation sensed adequately at ≥ 1.0 mV in normal sinus rhythm (NSR), but only six patients had effective AMS at these settings in atrial fibrillation. Three of four patients who developed atrial flutter had effective AMS at ≥ 2.0 mV. AV Interval: AMS was effective in eight of ten patients at AV intervals up to 200 ms. One patient lost AMS at an AV interval of 120 ms. Algorithm: In two of seven patients, AMS was not effective if the detection algorithm was more stringent than five beats at 150 beats/min. Conclusions: (1) In atrial fibrillation, effective AMS requires more sensitive atrial settings than in NSR: (2) AV intervals as short as 120 ms can interfere with AMS function; and (3) More stringent detection algorithms may be inappropriate for effective AMS function.     

EPIDEMIOLOGY OF UPPER AERODIGESTIVE CANCERS AMONG ARMED FORCES PERSONNEL AND THEIR FAMILIES

Cancers of the oral cavity, pharynx, and esophagus are now suspected to have common etiologic factors and have been grouped together as “upper aerodigestive” cancers. Since this grouping is of relatively recent origin there have been no epidemiological studies on this group among Armed Forces personnel. 114 cases of upper aerodigestive cancers and an equal number of controls were studied. The largest number of cases were in the age group of 40–49 years with male preponderance. Lower level of education, smoking, quid chewing, and alcohol use were found to be the major risk factors for these cancers. A dose response relationship was observed for smoking, quid chewing and alcohol intake.KEY WORDS: Neoplasms, Smoking, Quid chewing, Alcohol