Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.      

Length polymorphism of heterochromatic segment of the Y chromosome in boys with acute leukemia

The extent of length polymorphisms of the heterochromatic and euchromatic segment of the human Y chromosome were investigated in 15 boys with acute leukemia and were compared with 15 normal controls. A greater value of the Yh/F index in relation to controls was established (P < 0.05). The length of the euchromatic segment was also shorter in the patients than the controls (P < 0.05).     

Effects on Plasma Glucose Concentration of Light-for-date Infants and Infants of Diabetic Mothers of Feeds Supplemented with a Glucose Polymer

ABSTRACT. Serial plasma glucose estimations were performed in 44 light-for-date infants and 17 infants of diabetic mothers fed 2, 3 or 4-hourly with feeds containing 10 % additional carbohydrate in the form of a glucose polymer (Caloreen). In the infants fed 2 and 3-hourly, plasma glucose was higher following the high carbohydrate feeds, particularly immediately before the next feed was due. Given 4-hourly, the high carbohydrate feed had little effect in most light-for-date infants, and in one light-for-date infant and two infants of diabetic mothers the plasma glucose was lower at the end of 4 hours than following normal formula. It is concluded that the addition of glucose polymer to feeds given 2 and 3 hourly has a potentially useful effect in neonates at risk of developing hypoglycaemia, but it cannot be used to increase the feed interval to 4 hours.     

Pharyngeal diverticula

A series of 73 hypopharyngeal (Zenker's) diverticula is reported and the choice of treatment and technique of excision are discussed. The problems of excision include operation on an infected site with limited access but few patients are unfit for the procedure. Preoperatively the sac should be packed and the oesophagus stented. The side of approach is unimportant as the condition is essentially midline. Cricopharyngeal myotomy appears to reduce the recurrence rate, possibly by improving coordination of pharyngeal contraction and upper oesophageal relaxation. The use of electrocoagulation is not recommended as 20% of patients require repeated general anaesthesia and the procedure fails in 13%. For all but the smallest pouches, excision is the treatment of choice.     

Relation between colony formation in calcium-deficient medium, colony formation in soft agar, and tumor formation by T51B rat liver cells

T51B rat liver cells and several carcinogen-treated, carcinogen + saccharin-treated, or spontaneously altered clones of T51B cells were tested for their abilities to form colonies in calcium-deficient medium and soft agar and to produce tumors in athymic nude mice. Most (10 out of 11) of the clones which were derived from colonies in calcium-deficient medium were unable to form colonies in soft agar and 8 out of 11 were non-tumorigenic. Conversely, 6 out of 9 clones derived from colonies in soft agar were unable to multiply significantly in calcium-deficient medium and 5 of these 6 clones were also non-tumorigenic. Two of these 9 soft agar-growing clones were tumorigenic, one of which also proliferated in calcium-deficient medium, and the other of which acquired the ability to proliferate in calcium-deficient medium after it became able to form tumors in athymic nude mice. Thus, T51B rat liver cells gain the ability to grow in calcium-deficient medium and soft agar independently during the process of neoplastic transformation and neither characteristic by itself reliably predicts tumorigenicity.     

Increased cytokine secretion in patients with failed implants compared with patients with primary implants

All total joint replacements generate wear debris; yet, some implant prostheses fail while others survive despite the presence of ultrahigh molecular weight polyethylene particulate. It was hypothesized that patients with failed hip implants who have osteolysis will secrete higher inflammatory cytokines than patients receiving total joint replacements. Our study evaluated the peripheral blood monocyte response to varying polyethylene particle volume ratios through cytokine quantification in two patient populations: patients having revision surgery for failed total hip replacements (failed implant group) and patients having primary total hip surgery for osteoarthritis of the hip (primary implant group). We observed elevation of all three proinflammatory cytokines tested (interleukin-6, interleukin-1, and tumor necrosis factor-alpha) in response to polyethylene particulate challenge when compared with the controls in both patient groups. The population with failed implants also had a higher absolute cytokine response to polyethylene exposure compared with the control patients having primary implants. These findings suggest that patients with failed implants have a greater inflammatory cytokine response to polyethylene than seen in patients with primary implants.