Cytodifferentiation of pituitary primordia transplanted to the kidney capsule of adult hosts

This study demonstrates the ability of pituitary anlagen from 12- and 15-day embryonic rats to undergo cytodifferentiation in a site distant from that of its normal juxtaposition with the hypothalamus. Pituitary anlagen (PA) were isografted from 12- and 15-day-old embryonic donors to under the kidney capsule of intact adult female rats. Seventeen days later the grafts were recovered and processed for light and electron microscopy (LM and EM). Four of six 12-day and all five 15-day PA grafts developed into adenohypophyseal-like tissues. At the light as well as EM level, no consistent quantifiable differences could be detected between the glandular tissues that developed from the two different donor groups. While most of the cells within anterior pituitary-like tissue were chromophobic at the LM level, some cells were stained positive with periodic acid-Schiff and Orange G. Examination by EM revealed that most cells within the glandular portions of the grafts were granular and that these cells could be grouped into three general categories based on their secretory granule morphology. The sizes of the secretory granules ranged from 150-550 nm in diameter. Clear examples of exocytosis of the granules were evident in grafts of both 12- and 15-day PA, usually in areas of the graft that were more vascularized. In some cells exocytosis was extensive. Agranular cells in the graft parenchyma included follicular and undifferentiated cells. The results of this investigation suggest that kidney capsule grafts may prove useful in elucidating the factors that influence pituitary development.     

Early time course of recruitment of immune surveillance in human skin after chemical provocation.

As part of the defence function of skin it seems probable that mechanisms exist for the rapid recruitment of immune surveillance to 'inspect' any foreign substance that penetrates the skin. In the present study, evidence of such mechanisms was sought by following the time course of early changes in distribution of immune cells, expression of cell adhesion molecules and cytokines after epicutaneous challenge with provoking chemicals to which subjects were known to be either specifically 'sensitive' or 'non-sensitive'; anthralin, an irritant chemical, was used as control. Fifty-seven individuals were studied and there were at least five biopsy samples at each time point. Regardless of whether individuals were sensitive or not, or of the type of chemical, dermal microvascular endothelial cells showed increased expression of the adhesion molecules ELAM-1 and VCAM-1 within 2 h, and ICAM-1 within 8 h. The intensity of immunohistochemical staining increased progressively up to 24 h. More vessels stained for ICAM-1 than for VCAM-1 or ELAM-1, implying that not every vessel expressed all three cell adhesion molecules. Another early change, observed 2 h after irritant challenge, was a significant increase in numbers of CD1a+ dendritic cells in the superficial dermis from a median of 3/high power field (hpf) to 9.5/hpf (P < 0.03). This was not observed with 'weak' provoking substances, such as nickel, but did occur with the potent provoking agent dinitrochlorobenzene (DNCB). Thus, as little as 2 h after contact with provoking chemicals, the skin activates cellular mechanisms to increase T cell infiltration for the presumed purpose of immune surveillance. These mechanisms are not dependent upon specific immune sensitivity and reflect a capacity of skin cells to respond to chemical provocation.     

The variable anatomy of the nerve to the extensor carpi radialis brevis

The origin and course of the nerve to the extensor carpi radialis brevis are closely related to the lateral aspect of the elbow joint and proximal portion of the radius—both of which are frequent sites of pathology and surgical treatment. The specific origin of the nerve supply to the extensor carpi radialis brevis muscle has been attributed variably by diverse anatomic and clinical texts to be the radial nerve, its deep branch or its superficial branch. This study was undertaken to determine the most common source of the nerve to the extensor carpi radialis brevis, as well as the most predictable topographic site of its origin. A total of 111 limbs were dissected, with the most common origin (56.7%) found to be the deep radial nerve, followed by the superficial branch of the radial nerve (31.5%), and least frequently from the bifurcation of the radial nerve into its superficial and deep branches (11.7%). This nerve branch was found to arise in most individuals within one centimeter of the distal edge of the humeroradial joint and to pass distally about 3.5 centimeters before entrance into the extensor carpi radialis brevis muscle. © 1993 Wiley-Liss, Inc.     

Extracorporeal shock wave lithotripsy for urinary tract stones using MPL 9000 spark gap technology and ultrasound monitoring

Between November 7, 1988 and December 31, 1989, 881 treatments were given with the MPL 9000 lithotriptor to 513 sites in 510 renal units in 464 patients. Of the stones 447 (87.1%) were in the kidney, 64 (12.5%) in the ureter and 2 (0.4%) in the bladder. Stone size was up to 2 cm. in 58.5% of the cases, greater than 2 to 3 cm. in 25.8% and more than 3 cm. in 15.7%, including complete or partial staghorn, or multiple stones. Of the patients 54.2% received only 1 treatment, 17.6% received 2 treatments and 28.2% received more than 2 treatments (re-treatment was necessary in 45.8%). The number of shocks used varied from 610 to 4,000 at 14 to 24 kv., the usual energy used being 18 kv. Of the stones 30.2% were treated after Double-J stents were inserted. A patient was declared stone-free only when no stone particle was visible on a plain abdominal x-ray (or ultrasound if the stone was radiolucent). X-rays 3 months after extracorporeal shock wave lithotripsy (ESWL) were available for review in 397 patients (79.9%) and 72.8% were stone-free (with the aforementioned criteria) at 6 months (61.5% without ancillary procedures and 11.3% after ancillary procedures). Of a subset of 106 patients 84% were stone-free within 3 months when ESWL was restricted to a smaller stone burden, the number of shock waves administered was increased and energy was restricted to 14 to 18 kv. Over-all, 9.1% of the patients needed ancillary measures, including percutaneous nephrostomy in 1.6%, push-back for ESWL in 1.9%, ureterorenoscopy in 5.4%, percutaneous nephrolithotomy in 0.6% and pyelolithotomy/ureterolithotomy in 2.8%. The MPL 9000 device has the unique combination of electrohydraulic shock wave generation and ultrasound monitoring. The latter attribute has the distinct advantage of avoiding radiation to allow for visualization of nonopaque renal and gallbladder calculi. In addition, because there is continuous stone visualization during fragmentation accurate stone targeting can be maintained. The combination of ultrasound monitoring and spark gap technology allows for effective stone fragmentation.     

Immunocytochemical localization of follicle regulatory-protein (FRP) in testis

Follicle regulatory protein (FRP) can exert paracrine control over follicular development. It is synthesized by the granulosa cells of the developing follicles and was localized in the cytoplasm of the mural cells by immunocytochemistry. When administered to male dogs and rats, FRP causes impairment of spermatogenesis. In the intact male rat, it has been postulated that FRP manifests its effects at a stage prior to the conversion of testosterone to dihydrotestosterone. Sertoli cells of the seminiferous tubules are implicated in testosterone metabolism. Furthermore, Sertoli cells in male gonads are regarded as the counterpart of granulosa cells in ovaries. The exact source of FRP in the male is not known. Therefore, it was of interest to study the localization of FRP in the male gonads. Testicular sections of the pig, dog, cat, rat, mouse, monkey, and man were immunocytochemically stained with monoclonal antibody to porcine FRP of ovarian origin. Sections of pig ovaries were used as controls throughout the study. Specificity of immunocytochemical localization was established by preabsorption. FRP antibody predominantly localized to the interstitial compartment of the pig testis. In the seminiferous tubules, FRP localization was limited to basal spermatogonia and Sertoli cells of tubules at few specific stages of spermatogenesis. The study also showed that the monoclonal antibody against porcine FRP is species-specific. Antibody binding was found only in pig testis, whereas tissues from the cat, dog, mouse, rat, monkey, and man did not display any immunocytochemical reaction. Since in the pig testis, Sertoli cells at specific stages of spermatogenesis showed FRP localization, it would appear that FRP production is not being carried out by Sertoli cells at other stages. Due to the fact that all of the interstitial cells stained with FRP and some of the Sertoli cells were stained with FRP-antibody, it is not possible to ascertain the exact cell type responsible for FRP synthesis and secretion in testis using immunocytochemistry. Since the antibody to FRP of ovarian follicular fluid origin bound to various testicular cells, it would appear that FRP or a protein of similar nature may also be present in the testes.     

Cigarette smoking among marijuana users in the United States.

The vast majority of drug users smoke cigarettes. Most use marijuana and no other illicit drug. We analyzed adult responses to the 1997 NHSDA (n = 16,661) to explore relationships between marijuana use and cigarette smoking. Multivariate analyses controlled for other illicit drug use and other potential covariates. Nearly three-quarters of current marijuana users (74%) smoked cigarettes. Compared to nonusers, the adjusted odds of being a smoker were 5.43 for current marijuana users, 3.58 for past year marijuana users, and 2.02 for former marijuana users. Odds for cigarette smoking among current poly-drug users, compared to nonusers, were 2.3 to 1. Level of cigarette smoking was directly associated with frequency of marijuana use. Nationwide, an estimated 7 million adults smoke both substances and are at increased risk for respiratory illnesses and mortality. Cigarette smoking is a major co-morbidity of marijuana use and smoking cessation should be addressed among marijuana users in addition to their other illicit drug involvement.     

Laparoscopic common bile duct exploration: the past, the present, and the future

BACKGROUND: The advent of laparoscopic cholecystectomy (LC) has created a dilemma for treating patients with known or suspected choledocholithiasis. With rapid technologic growth and experience in laparoscopic skills, many surgeons are now routinely performing laparoscopic common bile duct exploration (LCBDE) and questioning the wisdom of preoperative endoscopic retrograde cholangiography (ERC) with or without endoscopic sphincterotomy. The purpose of this article is to review the current literature on the subject of LCBDE and critically evaluate the clinical results of this emerging technology. METHODS: Medline and Science Citation Index databases were used to search English language articles published on LCBDE since 1989. RESULTS: Transcystic common bile duct exploration has a better clearance rate, and carries less morbidity and mortality compared with laparoscopic choledochotomy. Compared with two-stage ERCP and LC, one-stage LC and LCBDE seems to be associated with a shorter hospital stay, a quicker recovery, less expense, and less morbidity and mortality. CONCLUSIONS: LCBDE is a feasible, safe and effective procedure that carries a low morbidity and mortality and will decrease the need for unnecessary ERC in the future for suspected or proved choledocholithiasis.     

Predictors of the development of hyperkalemia in patients using angiotensin-converting enzyme inhibitors

BACKGROUND/AIMS: Angiotensin-converting enzyme inhibitors (ACEI) are the antihypertensives of choice in patients with chronic renal failure (CRF). ACEI by decreasing the synthesis of aldosterone, the main regulator of serum potassium, predispose to the development of hyperkalemia. Although hyperkalemia with administration of ACEI is uncommon in patients with a normal renal function, a preexisting abnormality in potassium hemostasis, as seen in patients with chronic renal failure, may increase the risk of hyperkalemia. METHOD: To determine the predictors of development of hyperkalemia (K >5.1 mEq/l) in patients on ACEI, we retrospectively reviewed medical records of 119 patients followed in our renal clinic. RESULTS: The mean age of the patients was 56 +/- (SD) 13 (range 20-84) years. Sixty-three percent were males, and 37% were females. Sixty-seven percent had a history of diabetes. Eighty five percent of the patients had CRF [creatinine clearance (CrCl) <80 ml/min]. The baseline serum Cr was 2.3 +/- 1.2 (range 0.6-6.9) mg/dl, and the CrCl was 50 +/- 27.5 ml/min. Of the 119 patients 46 (38.6%) developed hyperkalemia (mean K 5.68 +/- 0.3, range 5.2-6.7 mEq/l). Ninety-six percent of the patients who developed hyperkalemia had CRF, and 84% were diabetics. Pearson product-moment correlation revealed a significant positive correlation of hyperkalemia with Cr and a negative correlation of hyperkalemia with CrCl and HCO(3) (Cr: r = 0.42, p < 0.0001; CrCl: r = -0.34, p < 0.0001; HCO(3): r = -0.41, p < 0.0001). Multivariate logistic regression analysis revealed diabetes and serum creatinine to be the main predictors of hyperkalemia. In 31 patients hyperkalemia resolved either with a low-potassium (2 g/day) diet or with diet and a decrease in the dose of ACEI. In 15 patients ACEI had to be discontinued due to persistent hyperkalemia. CONCLUSIONS: We conclude that hyperkalemia is common in patients with CRF on ACEI. The majority of the patients who develop hyperkalemia on ACEI have CRF and diabetes. A large number of patients with CRF require discontinuation of ACEI due to hyperkalemia and are deprived of their renoprotective effects.