The Drosophila melanogaster sex determination gene sisA is required in yolk nuclei for midgut formation.

During sex determination, the sisterlessA (sisA) gene functions as one of four X:A numerator elements that set the alternative male or female regulatory states of the switch gene Sex-lethal. In somatic cells, sisA functions specifically in sex determination, but its expression pattern also hints at a role in the yolk cell, a syncytial structure believed to provide energy and nutrients to the developing embryo. Previous studies of sisA have been limited by the lack of a null allele, leaving open the possibility that sisA has additional functions. Here we report the isolation and molecular characterization of four new sisA alleles including two null mutations. Our findings highlight key aspects of sisA structure-function and reveal important qualitative differences between the effects of sisA and the other strong X:A numerator element, sisterlessB, on Sex-lethal expression. We use genetic, expression, clonal, and phenotypic analyses to demonstrate that sisA has an essential function in the yolk nuclei of both sexes. In the absence of sisA, endoderm migration and midgut formation are blocked, suggesting that the yolk cell may have a direct role in larval gut development. To our knowledge, this is the first report of a requirement for the yolk nuclei in Drosophila development.

Ascending aortic aneurysm with aortic valve incompetence--surgical management.

Aneurysm of ascending aorta with aortic valve incompetence is a formidable pathological entity having a relentless course. Etiological factors include syphilitic aortitis, dissection of aorta, Marfan's syndrome and similar conditions. With the advance in operative technique and extra corporeal circulation, now it is possible to treat these conditions by surgery. Surgical intervention includes replacement of entire ascending aorta along with aortic valve by an artificial valve conduit. Basically, two procedures are described, namely, the conventional method and Bentall's operation, both involving a great technique challenge. Our experience with both these techniques is being described in four consecutive cases in the last one year.

Blood cardioplegia--a comparative clinical and laboratory study.

A prospective comparative study was undertaken to determine quality of myocardial preservation during open heart surgery by crystalloid and blood cardioplegic solutions. Total 55 consecutive patients were studied. Alternate patients received blood and crystalloid cardioplegia at random. Group I had 30 patients who received crystalloid cardioplegia, and group II, with 25 patients, received blood cardioplegia. The efficacy of two solutions was assessed by serum enzyme estimation of creatinine phosphokinase, M.B. fraction of creatinine phosphokinase and serum glutamate oxalate transferase (CPK, CPK-MB, SGOT), electron microscopic study of Left Ventricular biopsy and clinical assessment of post anoxic cardiac performance. Group II patients had lower serum enzyme levels, lesser microscopic myocardial damage, and better cardiac performance during immediate post-operative period, thus proving superiority of myocardial protection by blood cardioplegia.

A clinical study of eye complications in leprosy.

A study was conducted to find out the incidence of ocular complications in leprosy. The ocular lesions were found in 6.6% of lepromatous leprosy and 1.6% in nonlepromatous leprosy. Out of 150 patients with eye lesions 74% were males and 80% belonged to lepromatous leprosy. The age group in all the patients varied from 3rd to 6th decade. Mean duration of leprosy ln lepromatous leprosy was 6.2 years. The important eye complication observed were lagophthalmos (8.1%), corneal ulcers (10%) and iridocyclitis (24%). The loss of eye-brows (76%) was found to be most frequent in this study followed by corneal lesion (62%). It is concluded that examination of eyes are essential in all types of leprosy.