Diagnosing neurofibromatosis type I in children

Neurofibromatosis is the single most common genetic disease of the neurologic system. Because neurofibromatosis type 1 (NF-1) is often diagnosed early in life, it is essential that health care providers deepen their understanding of this common genetic disorder. Children who meet particular criteria, as formulated by the National Institutes of Health, must be worked-up for NF-1 in order to initiate appropriate treatment implementation and evaluation. This article provides a review of the literature regarding the pathophysiology, clinical manifestations, and plan of treatment related to NF-1, specifically as it affects children. Clear guidelines for health care providers in primary care are outlined.     

Extent of radial sarcomere coupling revealed in passively stretched cardiac myocytes

We report a simple method, the PinPoint assay, for detecting and identifying single-base variations (polymorphisms) at specific locations within DNA sequences. An oligonucleotide primer is annealed to the target DNA immediately upstream of the polymorphic site and is extended by a single base in the presence of all four dideoxynucleotide triphosphates and a thermostable DNA polymerase. The extension products are desalted, concentrated, and subjected to delayed-extraction MALDI-TOF mass spectrometry. The base at the polymorphic site is identified by the mass added onto the primer. Heterozygous targets produce two mass-resolved species that represent the addition of both bases complementary to those at the polymorphic site. The assay is suitable for double-stranded PCR products without purification or strand separation. More than one primer can be simultaneously extended and then mass-analyzed. The mass spectrometric method thus shows promise for high-volume diagnostic or genotyping applications.     

Delay in resumption of the activity of tetracycline-regulatable promoter following removal of tetracycline analogues

The tetracycline-regulatable system (TRS) has become a widely adopted tool for modification of gene expression and analysis of gene function in mammalian cells, plants and transgenic animals. We have studied the potential application of the TRS in gene therapy, using a single vector containing both the tetracycline-controlled transactivator (tTA) and the tTA-responsive promoter (tRP) transcribing mouse GM-CSF. Stable 293 cells established using this vector were used to study the kinetics of the TRS in response to various tetracycline analogues. Dose-response studies show that doxycycline is the most potent-analogue in abolishing tTA activity. Kinetic studies indicate that, at 1,000 ng/ml, all the analogues have similar efficiencies in down-regulating the system in given time. In contrast, following the removal of the analogues, there is a temporal, dose-dependent delay in resumption of the tRP activity. The time taken for resumption of near-optimal tRP activity is approximately 48 h for tetracycline, 144 h for anhydrotetracycline, 192 h for minocycline and 216 h for doxycycline when cells were pretreated with 1000 ng/ml of these antibiotics. This property of the analogues can be employed in planning a desired course of transgene regulation.     

The ileal neobladder to the female urethra

In the author's opinion, in the properly selected woman undergoing radical cystectomy for transitional cell carcinoma of the bladder, the ileal neobladder to the female urethra is a viable option. Ten years of experience with 23 patients have led to a nerve and urethral support cystectomy technique with the ileal neobladder anastomosed to the proximal urethra. Even then, however, retention in 20% of patients rather than the expected incontinence is the critical issue. Incontinence has never been a problem. The advent of orthotopic lower urinary reconstruction in women is a major achievement in the evolution of urinary diversion. With our increasing understanding of the continence mechanism in women and with increasing evidence that the female urethra can be safely preserved after cystectomy, orthotopic lower urinary tract reconstruction by the ileal neobladder can now be offered safely not only to men but also to women undergoing cystectomy with superb functional results.     

Ulceration of the ileum in Crohn''s disease: correlation with vascular anatomy

Forty-five cases of gastroschisis and 85 of omphalocele were reviewed. The survival of gastroschisis has dramatically improved over the past 20 years, however, that of omphalocele still remained in the lower value, because the size of the defect and the presence of associated anomalies are prognostic factors. The primary fascial closure was first employed for the patients with gastroschisis and a silo chimney was used for limited cases. On the other hand, for the patients with omphalocele, primary closure was possible in 34 cases, silo chimney was used in 17, and 45 cases had nonoperative management with epithelialization. Among them, nonoperative management using painting was the most reliable therapeutic for omphalocele.     

CT of blunt trauma to the bowel and mesentery

Injuries to the bowel and mesentery are found in approximately 5% of all patients undergoing laparotomy after blunt abdominal trauma. Bowel and mesenteric injuries are often subtle and difficult to diagnose, and a delay in the diagnosis is associated with increased mortality and morbidity. CT is the best imaging method for diagnosing injuries to the bowel and mesentery. With meticulous scanning techniques, most significant bowel and mesenteric injuries can be reliably identified with CT preoperatively, and associated injuries to other abdominal viscera can be confirmed.     

Smith-Lemli-Opitz syndrome: phenotypic extreme with minimal clinical findings

The effect of spine venom from the crown-of-thorns starfish (Acanthaster planci) on drug-metabolizing enzymes in rat liver was studied. The spine venom was prepared by saturation of spine homogenate with ammonium sulfate and the protein fraction precipitating 50% saturation was used as venom B. Venom A was the protein precipitated between 50 and 100% saturation. When venom B (100-200 mg/kg) was given to rats, liver microsomal GSH S-transferase and cytochrome P450 activities decreased while cytosolic GSH S-transferase activity was not changed. The decrease in these microsomal enzyme activities was seen from 12 hr to 24 hr after giving 100 mg/kg of venom B. Rats given venom A died, suggesting an involvement of the lethal factor in venom A. The data showed that the spine venom B from A. planci depressed microsomal GSH S-transferase and cytochrome P450 activities in rat liver and that this venom was distinct from the lethal factor of the spine venom.