Failure of genetically selected miniature swine to model NIDDM

Ten young adult miniature swine from a line reported to be genetically selected for glucose intolerance and eight normal controls were obtained from Colorado State University. They were consecutively exposed to 4 mo of a high-fiber, low-fat standard swine diet; 4 mo of a high-sucrose, high-fat, low-fiber diabetogenic diet; and 4 mo of excess diabetogenic diet for obesification. Results of oral glucose tolerance and intravenous insulin tolerance tests conducted at the end of each regimen were compared. Hyperglycemia was not observed in any animals after any manipulation. Insulin sensitivity was also not influenced by diet. We conclude that F7 low-K miniature swine from this colony fail to model human non-insulin-dependent diabetes.     

Left ventricle in Noonan's syndrome. Electro-vecto-echo and angiocardiographic aspects

The electrocardiographic features of Noonan's syndrome have been known for several years, but the discordance between these electrical findings and the underlying haemodynamic disorders remains unexplained. In an attempt to elucidate the genesis of electrical abnormalities, we present here a retrospective study of 14 children with Noonan's disease, aged from a few days to 16 years and evaluated by electrocardiography, vectography, one- or two-dimensional echocardiography, angiography and His bundle electrophysiology. The electrocardiographic abnormalities observed concerned ventricular depolarization and intracardiac electric conduction with, notably, a QRS axis directed towards the right upper part of the electric field and a first degree infra-hisian atrioventricular block (His bundle potentials). Vectography showed in some cases an image of inferior pseudo-necrosis due to the absence of initial inferior forces; this image is highly characteristic. In other cases the QRS loop showed an image of left segmental block which is unusual in this type or cardiac pathology (pulmonary stenosis with or without atrial septal defect of the ostium secundum type).     

3-(Methylnitrosamino)propionitrile: occurrence in saliva of betel quid chewers, carcinogenicity, and DNA methylation in F344 rats

3-(Methylnitrosamino)propionitrile (MNPN), a potent carcinogen in F344 rats, was detected for the first time in the saliva of betel quid chewers at levels ranging from 0.5 to 11.4 micrograms/liter. The tumorigenic properties of MNPN and its potential to methylate DNA in F344 rats were evaluated. Groups of 21 male and 21 female rats were given 60 s.c. injections over a 20-week period (total doses 0.055 and 0.23 mmol per rat). The experiment was terminated after 106 weeks. MNPN at the higher dose induced 18 (86%) malignant tumors of the nasal cavity in male and 15 (71%) in female rats. The lower dose induced nine (43%) liver tumors. Groups of four or five male F344 rats were treated with a single s.c. or i.v. injection of MNPN (0.4 mmol/kg). MNPN was also administered to rats by swabbing the oral cavity (2.21 mmol/kg). The levels of 7-methylguanine and O6-methylguanine, formed 0.5-36 h after treatment, were measured in the liver, nasal mucosa, esophagus, and oral issues. The highest levels of methylated guanines were detected in the nasal cavity independent of the route of administration. The results of this study demonstrate that MNPN is present in the saliva of betel quid chewers and is a potent carcinogen in F344 rats.     

Influence of pregnancy, lactation, litter size and diet energy density on the stomach and intestine of sows

In the first experiment, 52 sows, each having raised one litter, were randomly assigned to the five following groups: control (nongravid) for pregnancy (CP), 110 d pregnancy (P110), control (nongravid) for lactation (CL), 4-wk lactation with 8 (L8) and with 12 (L12) piglets. In a second experiment, 36 sows, each having raised three litters, were randomly assigned to the following groups: control group (nongravid) fed a low-energy-density, 1% tallow diet (CLED) and two lactating groups, one fed the low-energy-density diet (LLED) and one fed a high-energy-density, 10% tallow diet (LHED). At slaughter, the stomach, small and large intestine and cecum were excised, emptied and freed from fat. Lengths and pre- and post-defatting weights were measured. Portions of tissues were homogenized and analyzed for protein, pepsin, maltase, RNA and DNA. Pregnancy had no effect on the weights of the different components of the gastrointestinal tract. Liver and small intestine weights were larger in lactating sows than in the CL group. Sows nursing 12 piglets had heavier livers than those nursing 8. The fundic mucosa of the latter had higher total pepsin activity and total protein and RNA contents than that of L12 sows. LHED sows had heavier small intestine and lower total pepsin content of the fundic mucosa than LLED sows.     

Diagnoses of the relatives of schizotypal outpatients

Relatives of 22 schizotypal probands were evaluated for lifetime psychiatric diagnoses. Forty-four (N = 44) of the 97 available relatives were interviewed directly using the Diagnostic Interview Schedule. The rates of psychiatric diagnoses were compared with those of sixty-six (N = 66) of 140 relatives of 30 depressed patients. Family history of mental illness was ascertained by the informant method on the remainder of relatives of both proband groups. The rate of depression found in the relatives of schizotypal patients was 52% in those directly interviewed and 25.7% when informants' reports on unavailable relatives are pooled with direct interview data. These rates were not significantly higher than those found for the relatives of depressed probands (34.8% by direct interview and 21% including reports from informants). The high rates of depression in the relatives of schizotypal probands may indicate that schizotypal personality is associated with affective disorder and not only with schizophrenia. However, the high rates may be due to the presence of depressive character traits in relatives, which inflate the rates of dysthymic disorder and other chronic depressive disorders in the relatives of borderline patients.     

Health risks among submarine personnel in the U.S. Navy, 1974-1979

This study evaluated health risks associated with U.S. Navy submarine duty by comparing hospitalization rates of submariners with surface ship personnel. The groups were compared using age-adjusted hospitalization rates for 16 major diagnostic categories and several specific diagnoses postulated to be submarine associated. Submarine personnel did not have significantly higher hospitalization rates for any diagnostic categories nor for any of the submarine-associated illnesses. Submariner relative risk of hospital admissions was greater for a few selected diagnoses but statistical significance was not attained. Submarine personnel had lower hospitalization rates for nearly all of the diagnostic categories examined. Reasons for these lower rates may be stringent screening of submariners, higher levels of education among submariners, difficulty of evacuation from a submarine, and the healthy-worker effect. The health status of U.S. Navy personnel does not seem to be adversely affected by submarine duty.