Buried ion-exchanged glass waveguides: burial-depth dependence on waveguide width.

A detailed theoretical and experimental study of the depth dependence of buried ion-exchanged waveguides on waveguide width is reported. Modeling, which includes the effect of nonhomogeneous time-dependent electric field distribution, agrees well with our experiments showing that burial depth increases linearly with waveguide width. These results may be used in the proper design of integrated optical circuits that need waveguides of different widths at different sections, such as arrayed waveguide gratings.

Lethal congenital non-spherocytic, non-immune hemolytic anemia with genital and other anomalies in two brothers.

Non-consanguineous healthy parents had 2 boys with severe, non-spherocytic, nonimmune hemolytic anemia, abnormalities of their external genitalia, flat occiput, dimpled earlobes, deep plantar creases, and increased space between their first and second toes. The birth of these children was separated by a spontaneous abortion at 3 months and delivery of a normal girl. We propose that these boys have a heretofore undescribed autosomal or X-linked recessive syndrome.

Emergent reuse leech therapy: a better method.

Tissues threatened by venous congestion often can be saved by timely leech therapy. Methods to restimulate sated leeches, particularly emergently, are only poorly described in the nineteenth-century literature. Sated leeches were purged of their blood meals by (1) posterior crop incision, (2) hypertonic saline (3 percent) immersion, (3) gentle finger pressure emesis, or (4) wood ash exposure. Their ability to reattach and refeed with or without serotonin stimulation was evaluated. All 20 leeches (100 percent) purged by posterior crop incision reattached, with 75 percent refeeding. After purging again, 87 percent of these refed leeches reattached, with 46 percent refeeding for a third time. Those leeches which did not initially refeed were exposed to serotonin 10 microM with 100 percent reattaching and 40 percent refeeding. None of the leeches purged by hypertonic saline immersion regurgitation reattached or refed. A single leech purged by finger pressure emesis reattached (20 percent) but did not refeed. After exposure to serotonin, two (40 percent) of each saline and finger pressure group reattached, with neither of the hypertonic saline group refeeding, while both finger pressure-purged leeches refed, consuming a meal 38 percent (+/- 29 percent) of original meal. None of those leeches which refed would reattach or refeed a third time. None of the wood ash-purged leeches reattached or refed even with serotonin exposure. The best method of purging leeches of their blood meals for emergent reuse is by posterior crop incision. Additional refeeding behavior can be achieved by immersion in serotonin 10 microM for 20 minutes.

Ultrasound debridement of trabeculated bone: effective and atraumatic.

Given the plethora of techniques available for debridement of contaminated bone, no single method can be considered ideal. Ultrasound has been shown to be less traumatic and more effective for debridement of contaminated soft tissue than either abrasive scrubbing or high-pressure jet irrigation. Using the distal femur and condyle of 23 freshly sacrificed adult Sprague-Dawley rats, this study was undertaken to compare ultrasonication to traditional debridement techniques in (1) their effectiveness in decontaminating trabeculated bone, (2) the subsequent effect of each treatment on bone cell function as measured by protein synthesis, and (3) the direct mechanical effects of each technique on the integrity of the bone structure itself. Ultrasonic debridement was found to be as effective as high-pressure jet irrigation or surgical scrubbing in debridement of contaminated trabeculated bone (no significant statistical difference). Overall activated bone cell function 24 hours after each debridement technique also was found to be equivalent (no significant statistical difference). However, electron microscopy reveals radical structural alterations of the bone after high-pressure jet irrigation or abrasive scrubbing that are not seen with ultrasound debridement. Acutely, the devastating effects of abrasive scrubbing and high-pressure jet irrigation leave an exposed bone matrix not only devoid of any cells but also honeycombed with interstices for entrapment of bacteria and other contaminants. All three debridement methods leave the deeper bone cells viable, but only ultrasound maintains the integrity of the directly involved bone trabeculum to reduce contamination, prevent colonization, and decrease possible infection.

Evaluation of a temporary arteriovenous shunt to establish neovascularization in a musculocutaneous flap: an experimental study.

On the dorsum of adult Sprague-Dawley rats, 3 x 7 cm pedicle flaps were raised and a temporary arteriovenous shunt (AVS) from anastomosis of the tail artery and vein was placed beneath. Fourteen, 21 and 28 days later, the pedicle flaps were converted to island flaps leaving only the AVS attachment. The degree of subsequent flap viability was directly related to the amount of time before flap conversion. At 14, 21 and 28 day intervals, there was 33.4%, 73.5% and 98% flap viability, respectively. Long-term AVS patency was found not to be required for flap survival. Normal hair growth, quantity and quality, occurred in only the 28 day delay group. Microangiography and histologic examination revealed extensive neovascularization from both the AVS artery and vein extending into the muscle, subcutaneous tissue and skin layers of each island flap. In summary, neovascularization of a large random pattern musculocutaneous island flap is possible using a temporary arteriovenous shunt. Flap survival is directly related to the length of time between AVS placement and cutaneous pedicle division, although long-term AVS patency is not required for continued flap viability. Hair growth may directly reflect the degree of underlying neovascular maturation. This AVS neovascularization technique could be applied to create new donor sites for free tissue transfer.

Benign testicular tumors in children with congenital adrenal hyperplasia.

The association between testicular tumors/nodules and congenital adrenal hyperplasia (CAH) has been previously reported. From 1960 to 1989, three patients (13 to 18 years old) with long-standing CAH developed testicular masses. Two patients with 21-hydroxylase deficiency were diagnosed in the neonatal period while one other with 11-hydroxylase deficiency was diagnosed at 3 years of age when he presented with sexual precocity. In all three patients, medical compliance was poor. The testicular masses were bilateral in two patients and unilateral in one, measured 1 to 2 cm, and occupied only the upper half of the testicle. Testicular biopsy specimens were obtained after at least 6 months of evidence of compliance with the adrenocorticotrophic hormone (ACTH) suppressive medication and failure of the nodules to regress. On gross examination the masses appeared to be firm yellow brown nodules. Light microscopy showed interlacing strands, cords, and rests of cells resembling interstitial (Leydig) cells but with no Reinke crystalloids. Electronmicroscopy in all patients showed variable amounts of both smooth and rough endoplasmic reticulum, the later with occasional dilated cisternae. Follow-up ranged from 6 months to 6 years. No further surgical treatment has been necessary. There has been no evidence of recurrence, distant metastases, or secondary malignancies during the time of follow-up. These findings suggest that testicular tumors may develop from chronic excessive ACTH stimulation of a putative pluripotential testicular cell, a Leydig cell, or an adrenal cortical rest. Unlike other testicular tumors these do not require orchiectomy as the initial form of therapy.

Leech therapy: when once is not enough.

Venous congestion is a constant threat in the survival of free flaps, pedicled flaps, tissue replantations and traumatized tissue. Leech therapy has proved effective in salvaging much of these compromised tissues. To be effective, leeches must be both readily available and hungry, requirements not always easily met. Our investigation seeks to establish a means to return sated leeches to their previous unfed, hungry state for reuse. Sated leeches were purged of their blood meals by placement in 3% hypertonic saline or by gentle finger pressure, then exposed to serotonin 0 microM (control), 10 microM, 30 microM or 90 microM for 20 min. Subsequent rebiting/refeeding was observed and analysed. Leeches bathed in serotonin rebit or reattached at nearly four times the rate of unexposed leeches; 30% vs 8% respectively. Biting, however, is not refeeding. Overall, 41 leeches were treated with serotonin with four (10%) refeeding. Those that refed consumed a significantly smaller blood meal than the initial feeding; 50% +/- 47% SD vs 348% +/- 143% SD of original body weight. None of the control group refed. As a method for routinely reusing leeches, serotonin bathing cannot be recommended. In the immediate postoperative period with the sudden emergence of venous congestion requiring leech therapy, but with an inadequate number available, this 20% [corrected] refeed rate after 10 microM serotonin exposure could potentially determine the success or failure of the flap/replantation until fresh leeches are made available.

Comparison of transient ischemic colitis with that requiring surgical treatment.

The records of 27 patients with colonic ischemia were reviewed. Twelve patients had typical reversible or transient ischemic colitis. Thirteen patients had an ischemic stricture or gangrene of the colon that required operation. Two of the patients have asymptomatic strictures of the splenic flexure and are under observation. The sigmoid colon in our series of patients was the most frequent area of symptomatic stricture formation. Any patient with ischemic colitis, especially that involving the sigmoid colon, should be observed closely for the development of a stricture. Surgical intervention is indicated only after colonoscopy and careful evaluation of symptoms and risk factors.