Postvasectomy residual sperm pregnancy

A pregnancy occuring within a few months after a successful vasectomy is sometimes attributed by a skeptical physician to sexual involvement by the spouse with a nonvasectomized man. This assumption may be unjustified because of the fact that after a vasectomy, some residual sperm which are viable enough to cause pregnancy could remain stored distal to the site of occlusion. The Maternal and Child Health Center of Taiwan documented a case history of a 32-year-old father of 2 who impregnated his wife approximately 38 days, and at least 9 ejaculations, after a successful vasectomy. The patient had no urogenital abnormalities and had an uneventful vasectomy procedure. He resumed intercourse with his wife 8 days after vasectomy and returned for 5 semen tests during the year after vasectomy. The patient's 28-year-old wife had her last menses 24 days after the vasectomy, and pregnancy test 57 days after the vasectomy confirmed the suspicion of pregnancy. Vacuum aspiration terminated the pregnancy 2 days later. There was no doubt or question at all that the patient was his wife's only sexual partner. The authors concluded that based on examination of several thousand postvasectomy semen specimens, the distribution of the biologic limits for residual sperm viability is an asymmetrical distribution skewed to the right, suggesting that the limits may even exceed 38 days for some individuals. Thus physicians should be careful in evaluating a pregnancy which occurs a few months after a successful vasectomy.     

Bronchial asthma,delayed cutaneous response caused by enviromental pollen and fungi (analysis of 250 children)

The metabolic effects of sodium restriction, alone or with thiazide, were studied in 12 healthy subjects, in 24 tetraplegics during the intial 8 months of paralysis (early) and in 16 others during the subsequent period (late). The diuresis caused by both treatments led to more haemoconcentration in early than in late patients. In contrast with the healthy subjects on low sodium, the tetraplegics had a delayed urinary sodium retention and no fall in calciuria. During thiazide, urinary sodium depletion occurred early and the urine calcium fell after 3 days in all tetraplegics. During both treatments, aldosterone and renin increased more in early patients than in the other groups. The clinical implications of inducing dehydration and a sustained stimulation of the renin-angiotensin-aldosterone axis in recently injured tetraplegics with severe orthostatic hypotension are discussed.     

Determination of benzene and its metabolites: application in biological monitoring of environmental and occupational exposure to benzene

Methods for the biological monitoring of benzene and its metabolites in exhaled air, blood and urine are reviewed. Analysis of benzene in breath can be carried out by using an exhaled-air collection tube and direct analysis by GC or GC-MS; however, this technique is less reliable when compared to analysis using blood or urine. For the determination of non-metabolized benzene in blood and urine, GC head-space analysis is recommended. Phenol, the major metabolite of benzene can be monitored by either HPLC or GC methods. However, urinary phenol has proved to be a poor biomarker for low-level benzene exposure. Recent studies have shown that trans,trans-muconic acid, a minor metabolite of benzene can be determined using HPLC with UV detection. This biomarker can be used for detection of low-level benzene exposure. Urinary S-phenylmercapturic acid is another sensitive biomarker for benzene, but it can be detected only by GC-MS. Hydroquinone, catechol and 1,2,4-benzenetriol can be measured using HPLC with either ultraviolet or fluorimetric detection. Nevertheless, their use for low-level assessment requires further studies. Eventually, for the assessment of health risks caused by benzene, biological-exposure reference values need to be established before they can be widely used in a field setting.     

Selective pulmonary vasodilation by inhaled nitric oxide is due to hemoglobin inactivation

BACKGROUND: Inhaled nitric oxide gas selectively decreases pulmonary artery pressure without affecting systemic arterial pressure. To determine if the selective pulmonary vasodilating effect of inhaled nitric oxide gas is due to inactivation by hemoglobin, we studied the ability of whole blood to inhibit the vasodilator activity of effluent from isolated lungs exposed to inhaled nitric oxide. METHODS AND RESULTS: The effluent from ventilated, Krebs-perfused rabbit lungs was passed directly over 3- to 4-mm rabbit aortic rings. Inhaled nitric oxide (150 ppm for 3 minutes) reduced pulmonary perfusion pressure, elevated by a continuous infusion of U46619, by 35 +/- 7% (mean +/- SEM, n = 5). Lung effluent from this series of experiments caused 40 +/- 13% relaxation of phenylephrine-preconstricted aortic rings. When blood was added to the combined lung/ring perfusion cascade (final hemoglobin concentration, 1 g/dL), inhaled nitric oxide again significantly reduced pulmonary perfusion pressure, but the effluent now failed to relax the aortic rings (30 +/- 6% [control] versus 1.5 +/- 1% [blood]). Both reduction in pulmonary perfusion pressure and relaxation of the rings during nitric oxide exposure were unchanged from control values after discontinuing the blood infusion. CONCLUSIONS: The presence of hemoglobin, even in extremely small amounts, restricts the vasodilating effect of inhaled nitric oxide gas to the pulmonary circulation.     

Tuberculous mesenteric lymphadenitis mimicking pancreatic carcinoma

Tuberculous mesenteric lymphadenitis is a rare clinical entity and non-surgical diagnosis of this condition remains a challenge. A 38-year-old Indian woman presented with a six-week history of epigastric pain, low-grade fever and anorexia. Upper endoscopy showed a gastric ulcer of the posterior wall of the stomach. On CT scan there was a 8 cm abdominal mass involving the pancreatic body and tail and the endoscopic ultrasonography was also compatible with a cystic pancreatic tumor which had eroded into the stomach. An exploratory laparotomy was performed and the diagnosis of tuberculous mesenteric lymphadenitis was confirmed by bacteriological and histological examinations. Medical therapy was started after surgery. At 18 months she is asymptomatic and abdominal CT scan is normal. Tuberculosis of mesenteric lymph nodes usually raises serious diagnostic problems. A high grade of suspicion is necessary in order to perform a pre-operative diagnosis.     

Glucagon-like and insulin-like hormones of the insect neurosecretory system

According to some investigators, trauma is thought to bring about physical changes which produce a coalescence of normally dispersed blood lipids into fat droplets and pulmonary fat embolisms. Lipemia is thought to increase the extent of this embolization. If this theory is correct, intravenously infused labeled oil which is retained in the lungs should be mixed with and diluted by the fat emboli originating from the blood. Radioactive olive oil of known specific activity was slowly administered to a) control rats, b) rats made lipemic by dietary measures, c) severely traumatized rats, and d) traumatized lipemic rats. There was no difference in the specific activity of the oil recovered from the lungs of rats of any group, indicating that no recognizable amount of blood lipids had been added to the experimentally produced emboli.