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Biomedical subjects

N D Fischer

Publications and source records attributed to N D Fischer.

At least 19 recordsLinked to original sources
PubMed1985

Tracheal reconstruction with pedicled thyroid cartilage.

Limited areas of tracheal stenosis have been repaired with a variety of techniques. More extensive upper tracheal defects present a greater challenge with less predictable success. The following is the description of yet another technique for reconstruction of extensive upper tracheal defects. We report on the use of a muscle-pedicled thyroid alar graft which carries its own blood supply and perichondrial covering, supplies a large, conveniently shaped graft, requires one operative site and one operative sitting, and has proven advantageous even in the comprised patient.

Humans↗
PubMed1981

Effect of ethaverine hydrochloride on cochlear microcirculation.

The effect of ethaverine hydrochloride on cochlear microcirculation was observed in short-term experiments on 11 guinea pigs. In these experiments, the endocochlear PO2, endocochlear potential (EP), cochlear microphonic (CM) potential, and blood pressure (BP) were recorded. Endocochlear PO2 was measured polarographically by gold electrodes in the scala media. Ethaverine hydrochloride was administered by intravenous infusion for ten minutes in doses of 2, 5, and 10 mg/kg. These experiments demonstrated that ethaverine hydrochloride in doses of 5 and 10 mg/kg caused significant elevation of endocochlear PO2 for 35 to 90 minutes, even when the BP temporarily declined. At the same time, it was observed that this improvement of cochlear microcirculation coincided with an increase of the CM potential. Decrease of the EP is probably the result of BP decline and a direct action of ethaverine on EP generation.

Acoustic Stimulation↗
PubMed1980

Effects of laser, scalpel, and electrosurgical excision on wound contracture and graft "take".

Current literature recommends the use of a carbon dioxide laser for excision of lesions where minimal damage and wound contracture are desirable. The extent of tissue damage is evaluated as a correlate of percentage of split-thickness skin graft "take" following excision of full-thickness skin with scalpel, electrocutting current, or carbon dioxide laser. The poorest overall percentage "take" is apparent following laser excision, while the highest overall percentage "take" occurs following scalpel excision. Wound contracture, an inherent part of wound healing, is reportedly minimal or clinically inapparent with laser excision. On the contrary, this experimental evaluation suggests that wound contracture following laser excision is at least as great if not greater than that following other methods of excision when a split-thickness skin graft is applied to the wound bed.

Animals↗
PubMed1980

Frontal sinus trephination: a new technique for office procedure.

A new office technique for frontal sinus trephination is described. The procedure is simple, expedient, and inexpensive. Our experience with 16 patients suggests that this procedure is reasonably safe and, in addition, avoids the often-seen complications of supratrochlear nerve injury and persistent noticeable scar.

Frontal Sinus↗
PubMed1979

Avoidance of early complications following radical neck dissection.

Multiple factors are associated with the increased risk of postoperative complications following radical neck dissection. Most significant of these are preoperative radiation and entry into the pharynx. The most common of these complications are discussed, and following is a description of preoperative, intraoperative, and postoperative methods to reduce them. Changes in operative methods and antibiotic coverage were associated with a decrease in wound infection and fistula formation. It is suggested that patients in high risk categories be covered with preoperative, prophylactic gram positive antibiotic coverage, along with Tobramycin.

Bacterial Infections↗
PubMed1978

A correlation of the effects of normoxia, hyperoxia and anoxia on PO2 of endolymph and cochlear potentials.

Change in PO2 in endolymph, endocochlear potentials and cochlear microphonics have been tested in normoxia, hyperoxia and anoxia on 24 guinea pigs. The polarographic method and construction of oxygen-sensitive microelectrodes is described in detail. The normal level of PO2 in endolymph vaires between 20 and 30 mm Hg. One-minute anoxia induced by breathing 100% N2 caused a decline in PO2, EP and CM, but during recovery only PO2 returned with over-correction to the preexposure level. Hyperoxia evoked by breathing 100% oxygen failed to increase the cochlear potentials and the PO2 in the endolymph. This suggests that vasoconstriction most likely occurs proximal to the capillaries bed of the stria vascularis.

Animals↗
PubMed1977

Perilymph fistulas secondary to gunshot wound. Localization with a radioactive pharmaceutical.

The symptoms, clinical evaluation, routes of formation, and repair of perilymph fistulas are reviewed. We report a case with oval and round window perilymph fistulas secondary to a gunshot wound. A radioactive pharmaceutical was injected into the subarachnoid space in the lumbar area. Subsequent radioactivity was detected at the sites of the fistulas. We discuss the implications and a suggested technique for fistula detection.

Adult↗
PubMed1977

Rhinocerebral mucormycosis.

Mucormycosis is a fulminant fungal infection occurring in debilitated patients with an underlying pathologic condition. The rhinocerebral form of the disease, which comprises nearly one half of recently reported cases, is most often found in uncontrolled diabetics or profoundly dehydrated children. Infection usually begins in the nose and progresses through the paranasal sinuses, invading the orbit and CNS secondarily. Despite the known pathogenesis of this disease, the ophthalmologist is often first to consider the diagnosis, due to inadequate intranasal examination by the primary physician. The delay caused by late occurrence of orbital manifestations has resulted in poor survival rates, despite vigorous therapy. In recent years, increased physician awareness has led to earlier diagnosis of rhinocerebral mucormycosis. This report presents 13 cases with which we have delt since 1963. The long-term survival rate is 85%. Aggressive surgical therapy, with repeated debridement, in combination with intravenous amphotericin B, have led to this high rate of cure.

Acidosis↗
PubMed1977

Laryngotracheoesophageal cleft. Diagnosis, management, and presentation of a new diagnostic device.

Congenital posterior clefts between the laryngotrachea and the esophagus have rarely been encountered as evidenced by only 30 cases reported in the world literature. Of these, patients in nine have survived. We present another patient with this condition who was successfully treated. Important aspects in evaluation, including the need for an experienced endoscopist and cineradiography, are discussed. Postoperative management using a continuous infusion pump to administer formula per gastrostomy prevents gastric distension and emesis that lead to stress on the closure. This should be a basic consideration in the management of these patients.

Diagnosis, Differential↗
PubMed1976

Outer hair cell loss and alterations in glycogen due to tobramycin sulfate.

A total of 26 albino guinea pigs were treated with 200 mg/kg/day of tobramycin sulfate. Animals were killed at various intervals of up to three weeks after seven days treatment. Outer hair cell (OHC) loss of the organ of Corti was evaluated by surface preparation techniques, and glycogen was assessed with PATCO- and PAS-stained sections. We have concluded that permanent damage of OHCs is most prevalent in areas that normally have the least amount and the smallest granule size of glycogen. With treatment, these susceptible areas are the least responsive in terms of an early increase in glycogen production. Furthermore, by 21 days after seven days of treatment, these same areas will reveal an almost total loss of glycogen at a time when damage is maximal.

Animals↗
PubMed1976

Ototoxicity of tobramycin sulfate.

Fifty-four healthy guinea pigs were studied histologically for evaluation of Tobramycin sulfate ototoxicity. They were treated with 50, 100, 150 and 200 mg/kg/day under different schedules. Loss of hair cells occurred when dosage of 1,200 mg/kg was reached. Animals receiving 700 mg/kg were without damage to the inner ear. Outer hair cell loss occurred first in the basal turn, spreading upward. Inner hair cell loss began in the apical turn, progressing downward. When a total dose of 1,400 mg/kg was reached by (two) different schedules the higher daily dose produced about twice the hair cell loss; therefore, the ototoxic effect depends on the total dose but even more on the increased blood concentration.

Animals↗