Role of nisoldipine on blood pressure, cardiac hypertrophy, and atrial natriuretic peptides in spontaneously hypertensive rats

The effect of long-term treatment with the calcium antagonist nisoldipine on development of hypertension, cardiac hypertrophy, and plasma levels of atrial natriuretic peptides (ANP) was determined in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) of the same age. Measurement of immunoreactive ANP in plasma provided a sensitive marker for the severity of hypertension and the associated cardiac overload. Long-term treatment with nisoldipine prevented the development of hypertension, the associated heart failure, and the increase of plasma levels of ANP in SHR but had no effect on systolic blood pressure, heart weight, and plasma levels of ANP in WKY. In addition, nisoldipine had a therapeutic effect in old SHR with manifest cardiac failure in end-stage hypertension, as evidenced not only by the reduction of blood pressure but also by the reduction of cardiac hypertrophy, of elevated immunoreactive ANP in plasma, and of increased plasma renin activity.     

Hirschsprung's disease in young adults

Hirschsprung's disease is rarely seen in the young adult, and presents unique problems in management because of the massive dilatation and hypertrophy that occur proximal to the aganglionic rectum or the rectosigmoid colon. The diagnosis, which may be suspected by barium enema, is confirmed by suction or full-thickness biopsy of the rectum that may be complemented by anal manometry. Based on our experience with eight patients, a two-stage surgical reconstruction is recommended, with a preliminary sigmoid colostomy through the normally innervated colon and an associated defunctionalized stoma constituting the initial operation. The distal colonic stoma permits cleansing of the caudal colon while the normally innervated proximal colon reverts to near normal caliber, usually within 2 to 6 months. This approach is in accord with the recommendation of Fairgrieve. Reconstruction using a Duhamel or Soave procedure has given good results. The Duhamel procedure seems preferable when a considerable discrepancy remains between the ganglionic and aganglionic segments of rectum.     

Factors relating to the sensory acuity of limbs with peripheral vascular insufficiency

We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.     

Choice of general practice for postgraduate training among medical graduates and undergraduates in Nigeria

A questionnaire survey of career choices was carried out among 112 medical graduates, after one year's internship (group I), during their National Youth Corps programme in Kaduna, Lagos, Cross River and Oyo states of Nigeria, and 365 final-year medical undergraduates (group 2) in the colleges of medicine in the corresponding states. A total of 13% in group I and 40% in group 2 were undecided as regards their first choice. Obstetrics and gynaecology was the most popular first choice in both groups. General practice ranked fifth among group I, but displaced surgery to rank second among group 2. The differences were statistically significant. A total of 41% of group I and 46% of group 2 preferred to work in a teaching hospital, reflecting the high preference for surgical specialties. Twenty-six per cent and 33.7% of respondents in groups 1 and 2 respectively wished to own their own practice or work in the private sector. General practice is a new specialty and its growth is supported by a national postgraduate training programme. A shift towards general practice is seen compared with previous studies of career preference among Nigerian medical graduates and students. This may be due to a changing balance of supply and demand in the medical work-force, or a better assessment of the nation's health problems and manpower needs.     

Near-infrared spectrophotometric monitoring of oxygen distribution to intact brain and skeletal muscle tissues

During continuous near-infrared optical monitoring of brain cortex and hindlimb skeletal muscles, anesthetized, ventilated cats were exposed either to progressive alveolar hypoxia, or to acute hemorrhage followed in some cases by resuscitation. Hypoxia decreased cytochrome a,a3 oxidation state in muscle more than in brain, while tissue blood volume increased in brain and decreased in muscle. At a PaO2 of 25 torr, cytochrome a,a3 oxidation level in the brain was sufficient to support EEG activity, but the cytochrome a,a,3 oxidation state in resting, innervated hindlimb muscle was near zero. Hemorrhagic hypotension invariably decreased cytochrome a,a3 oxidation state and tissue blood volume more in muscle than in brain, and muscle cytochrome a,a3 was completely reduced at about a 25-ml/kg blood loss. These observations, supported by noninvasively measured changes in near-infrared absorption in the tissues during serial intravascular injections of indocyanine green dye, indicate that different cytochrome responses to hypoxia and oligemia in muscle vs. brain tissue are attributable to different regional circulatory adjustments.     

Leuko-araiosis.

Leuko-araiosis is an unspecific radiologic sign, seen with CT scan or with MRI. It can be found as well in normal elderly persons as in pathological conditions. For the sake of clarity, CT scan and MRI images have to be distinguished. CT leuko-araiosis is linked with vascular risk factors and with age. The situation is more complex for MRI leuko-araiosis (likely on account of the higher sensitivity of MRI). Some images (caps and rims), frequently seen in normal, even young, individuals, are more frequent in aging. On the contrary, abnormal images at a distance from the ventricle are more difficult to interpret. Some of them are due to pathological well defined conditions (small infarcts, Binswanger's disease, cysts, plaques). Others may be secondary to remote pathologies (such as infarcts). Others are due to little specific conditions, such as perivascular dilatations ('état criblé' due to brain vasogenic edema, or to brain atrophy whatever its cause, and more frequently seen in the elderly). Other changes, such as incomplete infarction or myelin pallor with gliosis, have been described. At last, in some cases, no clearcut pathological lesion could be found. Leuko-araiosis may be present in primary degenerative dementia of the Alzheimer type, but it is neither necessary nor sufficient to establish the diagnosis of Alzheimer's disease, and it does not seem more frequent than in elderly controls. The mechanism of leuko-araiosis in Alzheimer's disease is likely multifactorial (for example, cerebral atrophy, amyloid angiopathy, associated hypertensive arteriolosclerosis could be involved). The relationship between leuko-araiosis, myelin pallor and white matter atrophy is poorly understood, and remains to be studied.