Fungal ring infiltrates in disposable contact lens wearers

PURPOSE

To report two cases of ring infiltrates in disposable contact lens wearers resembling Acanthamoeba keratitis but later identified as fungus.

METHODS

We report two patients with histories of disposable soft contact lens use, who, on initial presentation, were found to have corneal ring infiltrates and were treated for presumed Acanthamoeba keratitis. Microbiological studies, which included Gram stain and Gomori methenamine silver stain, as well as blood agar, chocolate agar, thioglycolate broth, Sabouraud agar, nonnutrient agar with Escherichia coli overlay, and Lowenstein-Jensen plates, were performed.

RESULTS

Microbiological studies revealed fungi in both cases.

CONCLUSIONS

Fungal keratitis is an uncommon complication of disposable soft contact lens use, but it should be considered in the differential diagnosis of corneal ring infiltrates.

Fungal keratitis in a daily disposable soft contact lens wearer

PURPOSE

To report the first case of fungal keratitis in a patient wearing daily disposable soft contact lenses.

METHODS

Case Report. A 20-year-old white female in good health developed a corneal ulcer in her lefteye associated with daily disposable soft contact lens wear. There was no history of trauma to the left eye, and she denied overnight wear. Corneal scrapings were taken, and the patient was started on intensive tobramycin 14 mg/mL and cefazolin 50 mg/mL topical therapy for suspected bacterial keratitis. After 3 days of antibacterial therapy, the ulcer worsened. The cultures were negative as were the Gram stain and Gomori's methenamine silver stain. Initial cultures and stains were then repeated with the addition of a culture for herpes simplex virus. The developing clinical picture was suspicious for fungal keratitis. The patient was then started on intensive vancomycin 2%, natamycin 5%, and continued on fortified tobramycin. Three days after the second corneal scrapings were performed, a positive fungal culture was obtained for Fusarium sp. Vancomycin and tobramycin were then discontinued and amphotericin B 0.15% was added to natamycin 5% with the continuation of intensive topical therapy.

RESULTS

The patient's keratitis was successfully treated with intensive double antifungal therapy.

CONCLUSIONS

Infectious keratitis in daily disposable soft contact lens wear is an unusual occurrence. To our knowledge, there is no previous case of fungal keratitis occurring in patients wearing daily disposable lenses. This case emphasizes the importance of considering fungus in the differential diagnosis for keratitis even in daily disposable contact lens wearers.

Diagnosis of hemophilia made after intraoperative bleeding during attempted penetrating keratoplasty in an elderly patient

PURPOSE

To report an unusual case where the diagnosis of hemophilia was made after attempted penetrating keratoplasty in an elderly patient.

METHODS

A 75 year old white male with a full-thickness corneal scar in the visual axis and a visually significant cataract OD was to undergo penetrating keratoplasty and cataract extraction with lens implantation for visual rehabilitation. There was no history of bleeding diathesis given.

RESULTS

During placement of the Flieringa ring, a progressively enlarging 360 degrees subconjunctival hemorrhage was observed. Given the unusual bleeding,the procedure was aborted and the patientwas referred to the hematology service for further evaluation. Laboratory studies revealed a diagnosis of atypical hemophilia of mild severity.

CONCLUSIONS

The initial diagnosis of hemophilia in any elderly patient is unusual. This case is even more unusual asthe diagnosis of a bleeding disorder was first considered after excessive subconjunctival hemorrhage developed during attempted penetrating keratoplasty.

Facial nerve injury following superficial temporal artery biopsy

BACKGROUND

With proper training, superficial temporal artery biopsy is a safe office procedure with few complications. Surgeons from different disciplines, including ophthalmologists, dermatologists, general surgeons, and plastic surgeons may be called upon to perform this common procedure to confirm giant cell arteritis.

OBJECTIVE

To emphasize the surgical anatomy of the scalp as it pertains to superficial temporal artery biopsy and to raise awareness that significant complications can occur after superficial temporal artery biopsy.

METHOD

Case report.

RESULTS

A 75-year-old woman with presumed giant cell arteritis developed frontalis muscle paralysis following a superficial temporal artery biopsy. Biopsy selection site within the danger zone combined with deep dissection carries the greatest risk of injury to the temporal branches of the facial nerve.

CONCLUSION

Any surgeon involved in the practice of performing superficial temporal artery biopsies should have a thorough understanding of proper surgical techniques and regional anatomy to avoid potential devastating complications.

Fungal keratitis after laser in situ keratomileusis: a case report

PURPOSE

To report a case of fungal keratitis resulting after laser in situ keratomileusis (LASIK).

METHODS

A 38-year-old white man in good health developed a corneal infiltrate with laboratory confirmation of fungal keratitis after LASIK. Corneal scrapings were taken. Silver stain was positive for hyphae. Culture was positive for Curvularia sp. The patient was started on intensive natamycin 5% and amphotericin 0.15% topical therapy.

RESULTS

The patient's keratitis was successfully treated with intensive antifungal therapy.

CONCLUSIONS

Infectious keratitis is a rare but a serious potential complication after LASIK. To our knowledge, no previous case of fungal keratitis after LASIK has been reported. This case emphasizes the importance of surveillance for infection after LASIK.

Mycobacterium chelonae keratitis after laser in situ keratomileusis successfully treated with medical therapy and flap removal

PURPOSE

To report a case of Mycobacterium chelonae keratitis after laser in situ keratomileusis successfully treated with medical therapy and flap removal.

METHODS

Case report. A 36-year-old white woman in good health developed a paracentral keratitis in her right eye 1 month after bilateral laser in situ keratomileusis. Initial treatment included topical steroids and then intensive Ocuflox (ofloxacin ophthalmic solution; Allergan, Inc, Irvine, California) without success. Cultures were negative. The keratitis worsened, and she was referred to our institution. Interface infiltration was noted, and the flap was lifted to obtain adequate laboratory studies. Cultures were positive for M chelonae.

RESULTS

The keratitis was treated with intensive topical amikacin sulfate 1%, topical clarithromycin 1%, and Ciloxan (ciprofloxacin HCL; Alcon Laboratories, Inc, Fort Worth, Texas) with minimal improvement in her clinical condition. She developed a toxic reaction to amikacin 1%. In order to improve antibiotic penetration, the hazy, ulcerated corneal flap was removed. The keratitis then resolved with intensive topical clarithromycin 1% and Ocuflox over 5 weeks. The patient now has visual acuity without correction of 20/50, despite superficial corneal haze.

CONCLUSION

M chelonae is a rare and insidious cause of infection after laser in situ keratomileusis. Diagnosis can be difficult and is often delayed. Aggressive medical management, with flap removal, if needed, may lead to resolution of infection.

Emerging fluoroquinolone resistance in bacterial keratitis: a 5-year review

OBJECTIVE

To identify resistance patterns to the fluoroquinolones for patients with bacterial keratitis.

DESIGN

Retrospective observational case series.

PARTICIPANTS

All cases of bacterial keratitis presenting to the Charles T. Campbell Ophthalmic Microbiology Laboratory at the Eye and Ear Institute of Pittsburgh from January 1993 to December 1997 were reviewed. A total of 1053 ocular isolates from 825 cases of bacterial keratitis were identified.

MAIN OUTCOME MEASURES

In vitro laboratory susceptibility testing of ocular isolates to ciprofloxacin and ofloxacin was determined by the Kirby-Bauer disk diffusion method and interpreted using the National Committee for Clinical Laboratory Standards serum standards.

RESULTS

The number of cases of bacterial keratitis per year decreased from 284 in 1993 to 75 in 1997. The ratio of gram-positive to gram-negative organisms changed from 81.8%:18.2% in 1993 to 51.4%:48.6% in 1997 (chi-square, 66.00; degrees of freedom, 4; P < 0.000001). Resistance of Staphylococcus aureus to ciprofloxacin significantly increased annually from 5.8% in 1993 to 35.0% in 1997 (chi-square, 19.80; degrees of freedom, 4; P < 0.0001) and for ofloxacin from 4.7% to 35.0% over the same period (chi-square, 21.32; degrees of freedom, 4; P < 0.001). Streptococcus species and coagulase-negative Staphylococcus species showed significant resistance to both fluoroquinolones but no change in resistance over the study period. The gram-negative organisms showed good susceptibility to the fluoroquinolones.

CONCLUSIONS

This in vitro study shows a significant increased resistance of S. aureus to the fluoroquinolones from 1993 to 1997. In addition, gaps in fluoroquinolone coverage for Streptococcus and coagulase-negative Staphylococcus species raise concern for the use of monotherapy in treating bacterial keratitis. Contrary to what might be expected, the distribution of gram-positive to gram-negative organisms has shifted, with a decrease in the number of gram-positive organisms identified, while the number of gram-negative isolates has remained stable.

Consistent responses of human mothers to prelinguistic infants: the effect of prelinguistic repertoire size

The salience of infants' vocal and visual cues was examined to evaluate the efficacy of prelinguistic vocalizations to guide adult behavior. A videotape, constructed of brief behavioral episodes from 3 infants with different-sized vocal repertoires, was played to 40 mothers of prelinguistic infants. Playback mothers' responses to the episodes were consistent, demonstrating that preverbal behavior elicits comparable reactions across unfamiliar receivers. The audio and video components of the infants' episodes were then recombined. As the vocal repertoire of the stimulus infants increased, changes in the audio component more often led playback mothers to change responses. Thus, playback mothers used vocalizations as cues as the infants' vocal repertoires became larger.

Conjunctival cysts of the orbit

OBJECTIVE

This study reviews functionally and anatomically disruptive features of simple conjunctival orbital cysts.

DESIGN

A case series review from four oculoplastic practices over 6 years.

PARTICIPANTS

Eleven patients with simple conjunctival cysts of the orbit were identified.

INTERVENTION

All cysts were excised and evaluated histopathologically.

MAIN OUTCOME MEASURES

Assessment was made of the length of time from inciting event to presentation, preoperative and postoperative refractive state and ocular motility, the presence or absence of discomfort, and radiographic or clinical evidence of bone remodeling.

RESULTS

Six of 11 cysts were presumed to be primary, unrelated to antecedent surgery or trauma. Four of 11 cysts were associated with pain or tenderness, 5 cysts induced ocular motility disturbance, 6 cysts caused observable globe distortion or refractive error change, and 6 cysts remodeled bone.

CONCLUSIONS

Simple conjunctival cysts of the orbit, traditionally regarded as low-pressure lesions with minimal structural impact, may induce considerable anatomic and functional disruption.

Comparison of mitomycin C trabeculectomy, glaucoma drainage device implantation, and laser neodymium:YAG cyclophotocoagulation in the management of intractable glaucoma after penetrating keratoplasty

PURPOSE

This study aimed to compare the surgical outcomes of mitomycin C trabeculectomy glaucoma drainage device (GDD) surgery and laser neodymium:YAG (Nd:YAG) cyclophotocoagulation (CPC) in the management of intractable glaucoma after penetrating keratoplasty (PKP) in a retrospective study.

DESIGN

Interventional case series.

PARTICIPANTS/METHODS

The medical charts of consecutive patients who had pre-existing glaucoma or who developed glaucoma after PKP and underwent a surgical procedure to control the glaucoma at the University Eye Associates of Boston University Medical Center, New England Eye Center, and Massachusetts Eye and Ear Infirmary between January 1991 and July 1995 were reviewed. Follow-up ranged from 6 months to 4 years after the glaucoma procedure. A total of 38 patients were included consisting of 17 patients who underwent mitomycin C, 10 patients who underwent GDD surgery, and 11 patients who had CPC.

INTERVENTION

Mitomycin C trabeculectomy, GDDs, or Nd:YAG CPC to control glaucoma after PKP was performed,

MAIN OUTCOME MEASURES

Graft status, postoperative intraocular pressure (IOP), and visual acuity were the main outcome measures.

RESULTS

There were no differences among the three groups with respect to the follow-up time after the corneal graft operation (P = 0.15) or after the glaucoma operation (P = 0.98). At the final follow-up, the average decrease in the IOP was 17 mmHg (P < 0.001) after mitomycin C, 15 mmHg (P = 0.003) after GDD surgery, and 14.4 mmHg (P = 0.001) after CPC. There were no differences in the proportion of patients who developed postoperative IOP above 20 mmHg (P = 0.50) and in the proportion who developed hypotony (P = 0.10) among the three groups. Two grafts failed after mitomycin C and one failed after CPC. Among the three procedures, there were no differences in the proportion of patients who experienced either an improvement (P = 0.14) or a decrease (P = 0.22) in the visual acuity by more than one line after the glaucoma procedure. One patient each in the GDD group and the CPC group lost light perception after the procedure. The risk of graft failure was almost three times higher for each additional PKP (odds ratio = 2.80, P = 0.02).

CONCLUSIONS

No differences were found among the three glaucoma procedures with respect to controlling IOP and graft failure. There was a trend for patients treated with CPC to have a higher incidence of graft failure, glaucoma failure, hypotony, and visual loss by more than one line, although this was not statistically significant. The number of PKPs was associated with graft failure, independent of the surgical procedure.

Neuroperceptual differences in consonant and vowel discrimination: as revealed by direct cortical electrical interference

The effects of direct cortical electrical interference on consonant and vowel discrimination were investigated in five patients with implanted subdural electrode arrays. Without electrical interference, patients performance discriminating consonants and vowels was intact. With electrical interference, consonant discrimination was impaired at one electrode site in each patient on the superior temporal gyrus of the lateral left perisylvian cortex. Conversely, vowel and tone discrimination remained relatively intact when tested with electrical interference at the same site. Analysis of patients' consonant discrimination errors revealed that neither differences in acoustic temporal structure nor syllable position fully account for the consonant-vowel perceptual dissociations elicited. Our data suggest that at the cortical level consonant and vowel perception are intrinsically distinct perceptual phenomena. The selective impairment of consonant, but not vowel, discrimination further suggests that consonant and vowel perception are distinguished by differences in relative dependence on the functional--perhaps integrative--resources of the left lateral superior temporal gyrus.

Habituation, sensitization, and infants' responses to motherese speech

Four-month-old infants were tested for their visual responses to infant-directed (ID) speech versus adult-directed (AD) speech in a fixed-trial habituation procedure. In Experiment I, infants looked significantly longer in response to a 4 x 4 checkerboard pattern that was compounded with an ID speech segment than an AD speech segment. Looking times increased significantly between the first and second presentations of the ID speech segment only. In Experiment II, infants looked slightly more during ID than AD trials when the two were alternated from trial to trial. Responding to the first AD speech segment was significantly greater than when it was preceded by ID speech than when it was not, while responding to the first ID speech segment was significantly less when it was preceded by AD speech than when it was not. These findings are discussed in relation to the hypothesized differential arousing properties of ID and AD speech.

The elastic flap for lip repair

These cases illustrate a new concept in lip repair. This approach recognizes the great inherent elasticity of the oral cavity and takes advantage of the florid blood supply of the region. Recent laboratory studies of Taylor et al., as well as the works of Manchot and Salmon, are combined with anthropologic observations of tribal customs to formulate another way of looking at lip reconstruction. Triangularization of surgical defects, lip switching, and mobilization of distant flaps are avoided by taking advantage of stretched local tissues. Preoperative expansion is discussed as a future option.

Morphologic variants of light-chain deposition disease in the kidney

A variety of histologic changes have been observed in the kidneys of patients with light-chain deposition disease. We report 3 cases with kappa light chain deposition who presented with diverse clinical, histological, and ultrastructural features. All the cases were diagnosed by the presence of monoclonal kappa light chain deposits by immunohistochemical methods. Based on the present study and review of literature, four basic patterns of glomerular lesions are identified: (1) minimal glomerular changes without glomerular deposits, but with extensive tubular involvement; (2) mild glomerular changes with glomerular deposits; (3) focal or diffuse proliferative glomerulonephritis with or without crescents, and (4) nodular glomerulosclerosis resembling diabetic glomerulosclerosis. This pathological and clinical variability can cause diagnostic problems at initial presentation. A high index of suspicion is necessary along with appropriate laboratory data and routine staining for light chains.

Unit study of monkey frontal cortex: active localization of auditory and of visual stimuli

The influence of sound localization behavior on unit activity in the frontal cortex of awake rhesus monkeys was examined by comparing responses under three behavioral conditions: auditory localization, during which a response was required to the location of a sound (broad-band noise) source; auditory detect, during which a response was required to indicate the occurrence of the sound regardless of location; visual localization, during which no sounds were presented and a response was required to the location of a visual stimulus; and nonperform, presentation of auditory stimuli as in the first two conditions, but with the animal sitting passively. Extracellular microelectrode recordings were made in the periarcuate region and dorsal and ventral prefrontal areas near the principal sulcus. Four monkeys were used with a total of 498 cells studied. Of the total population, only five cells were found to have characteristics similar to those of auditory units in the primary auditory cortex and the surrounding belt area. More typically, units were found that had strong short-latency responses specific to the auditory and/or visual localization tasks. These units had no or weak responses when the same sound stimuli were presented in the auditory detect task or when a monkey received the sound stimuli in a nonperforming condition. Two regions were identified, one medial and/or posterior to the arcuate sulcus, in Brodmann's area 6; the second included parts of areas 8 and 9 within the genu of the arcuate sulcus. Units from these regions are referred to, respectively, as the postarcuate and the prearcuate populations. Both populations responded predominantly during active localization behavior. Sixty-two percent of the postarcuate population responded during auditory localization, 32% responded during auditory detect, and only 18% responded to acoustic stimuli presented in the nonperforming condition. In the prearcuate population percentages in these three conditions were 35, 25, and 12%, respectively. For visual localization, 54% in the postarcuate population responded, whereas 42% in the prearcuate responded. Spatial tuning of units during auditory localization was similar to that seen in units of the primary auditory cortex, with the greatest percentages of units responding to stimuli contralateral to the recording site. Similar tuning was observed for the visual localization task as well. Similarities in spatial tuning between the auditory and visual localization conditions were examined to assess the "bimodal" nature of the units.(ABSTRACT TRUNCATED AT 400 WORDS)

A tissue-expanding vermilion myocutaneous flap for lip repair

An approach to lip reconstruction is described utilizing a myocutaneous vermilion flap based on the inferior labial artery. The inherent elasticity of the lip is used to great advantage by stretching the freed vermilion flap to bridge a loss of about one-half the lower lip. This vermilion flap may be worthy of consideration when reconstructing lip defects resulting from trauma (e.g., electric burns), tumor resections, and other congenital anomalies.

"Orbiting the orbicularis"--restoration of muscle-ring continuity with myocutaneous flaps

Eyelid repair by the Mustardé cheek flap or the Hughes tarsoconjunctival lid-sharing flap have been methods deservingly popular with plastic surgeons for many years. Recent attention given to the myocutaneous flap principle has prompted the formulation of a new approach to this difficult problem of replacing an eyelid. In these cases, we have taken what most plastic surgeons are currently "throwing away" in their blepharoplasties and used it to reconstruct up to an entire margin of the eyelid. This new method seems simple because it holds the promise of fewer procedures and perhaps more functional results.

Single-unit activity in the auditory cortex of monkeys actively localizing sound sources: spatial tuning and behavioral dependency

Single-unit recordings were made from the auditory cortex of unanesthetized rhesus monkeys which were trained to perform a second localization task. Recordings were made from 196 units in 4 animals. Five sound sources were located at 0 degrees (midline) and on either side at azimuths of 37.5 degrees and 75 degrees. Almost most units responded to each of the 5 sources, 49% of the units had peak firing rates for the source on the contralateral side at 75% azimuth. Another 26% of the units had peak firing rates at the 37.5 degrees contralateral location, while only 11% had peak rates for the ipsilateral locations. In order to determine whether the behavior of actively locating a sound source affected units in auditory cortex, response rates compared under two behavioral conditions: one which required the detection of a sound regardless of location and another condition which required identification of a sound's location. of the 196 units, 16 had different response rates for the two conditions, with 15 of the 16 units having higher evoked rates in the localization task. For the 16 units, the difference in firing rate was typically observed for a single speaker location. No correlation could be determined between a unit's location within the subdivisions of auditory cortex and its spatial tuning response properties or its dependency upon behavioral condition.

Cupula motion in the semicircular canal of the skate, Raja erinacea. An experimental investigation

An upper bound on the magnitude of semicurcular canal cupula motion was experimentally determined in the isolated labyrinth of the skate, Raja erinacea. To visualize the cupula, a glass pipette was pushed through the ampullary wall, and local regions of the cupula were stained by slow infusion of small amounts of Alcian Blue dye. Caloric stimuli which produced large changes in single unit activity in the ampullary nerve and which often recruited several larger, previously silent units were found to produce on detectable cupula motion as seen through the ampulla wall. However when the cupula was first grossly displaced, motion was thereafter observed in response to identical caloric stimuli. Analysis of afferent responses indicates that the normal range of cupula motion in the skate is below the optical resolution of the method, conservatively estimated as 3--5 micrometers.

Cupular movement and nerve impulse response in the isolated semicircular canal

The aim of the study was to record nerve impulse responses to controlled displacements of the cupula and relate these to observations of cupular motion. The preparation was the skate semicircular canal, isolated and maintained in a chamber. The canal was cut and tied tightly to an oil-filled tube driven by a 1 microliter syringe. In some experiments dye was used to make the face of the cupula visible. Small volume displacements (0.02 microliter) caused a billowing of the central portion of the cupula, whereas for repeated large displacements (0.1 microliter) the top of the cupula moved along the roof of the ampulla. Displacements of the latter amount were close to saturation in the characteristic functions (spike rate versus volume displacement) of nerve firing. It seems that the discharge rate of tonically responding units in the skate crista ampullaris rather faithfully record the force acting on the cupula. The motion of the base of the cupula rather than its tip appears to be the relevant parameter in setting the level of excitation in the sensory cells within the physiological range of stimulation. Such a mode of operation would ensure the highest sensitivity of the sense organ.

Effect of chronic furosemide administration on hydrogen and sodium excretion in the dog

Studies were performed to evaluate the effects of the chronic administration of furosemide on hydrogen and electrolyte excretion in dogs on a normal electrolyte diet and in the absence of electrolyte or volume depletion. Control daily excretion in five dogs averaged 64 meq for Na, 51 meq for K, 66 meq for Cl, and 17 meq for net H. Furosemide, 40 mg, in the drinking water 3 times daily was given for 4 days. On day 1 Na excretion averaged 128 meq, but thereafter was not significantly different from control levels. Over 4 days cumulative net H excretion increased 63.6 meq and plasma HCO3 rose 6.6 meq/liter. The same dogs were restudied by the same protocol except that, to obviate electrolyte depletion, NaCl and KCl were administered daily in quantities sufficient to replace urinary losses. All dogs remained in positive Na, K, and Cl balance. Body weight, hematocrit, plasma albumin, creatinine, and plasma renin activity were unchanged, indicating the absence of electrolyte or volume depletion. Nonetheless, cumulative net H excretion increased 61.2 meq and plasma HCO3 increased 4.3 meq/liter. Two adrenalectomized dogs receiving steroid replacement showed similar changes in net H excretion and plasma HCO3. These experiments suggest that chronic furosemide administration may enhance H excretion and generate alkalosis even in the absence of volume or electrolyte depletion and without increased aldosterone secretion.

Evoked unit activity in auditory cortex of monkeys performing a selective attention task

Single-unit responses were recorded from the auditory cortex of rhesus monkeys performing a selective atteintion task which used combined light and sound stimuli. The animals were first trained to push a lever to the left for a noise burst and to the right for a tone burst, and then trained to push left for a left light and right for a right light. Subsequently, one of the four possible light and sound stimulus combinations (Noise + Left Light, Noise + Right Light, Tone + Left Light, Tone + Right Light) was randomly presented on each trial. In blocks of 100 trials only one part of the combined stimulus (either the light or the sound) determined the direction of lever push that would be reinforced. Responses of single units to identical sound stimuli were compared for blocks in which sound was the relevant cue and blocks in which light was the relevant cue. Typically, differences were in response strength without alteration of response pattern. Even the earliest response components (15-20 msec latency) could show changes. Two-thirds of the response comparisons showed differences in strength depending upon whether sound or light was the relevant cue, with about as many responses stronger for light relevant as for sound relevant. Independent of which modality was relevant, unit responses for trials in which both parts of the combined light and sound stimulus indicated the same direction of lever push were generally stronger than unit responses for trials in which the two parts of the combined stimulus signalled opposite directions of lever pushes.

Treatment of idiopathic membranous nephropathy

In a retrospective study of the effect of treatment in biopsy-proved idiopathic membranous nephropathy, 91 adults and 12 children were followed for periods up to 29 years after clinical onset (mean, 6.5 years). Forty-four were treated with corticosteroids, 15 with corticosteroids and immunosuppressants; 44 had no treatment and served as a control group. Clinical cure and improvement were significantly greater in the treated than in the nontreated group (P less than 0.01). The recurrence rate, occurrence of renal failure and probability of death were significantly greater in the nontreated group, although some of these patients eventually showed improvement. Prognosis was better in patients who responded to therapy. These data strongly suggest that steroid therapy is beneficial in patients with membranous nephropathy.

Effect of sodium nitrate loading on electrolyte transport by the renal tubule

Effects of sodium nitrate were compared with sodium chloride loading on transport of electrolytes by the nephron. Maximal levels of free water clearance/clomerular filtration rate (CH2O/GFR) averaged 8.4% with nitrate loading and 14.4% with saline loading. Since ethacrynic acid and chlorothiazide exert their major natriuretic effect in the distal nephron, the increment in Na ad Cl reabsorbed beyond the proximal tubule. The administration of these agents resulted in an increase in fractional sodium excretion (CNa/GFR) of 21.1%, urinary sodium excretion (UNaV) of 1,126 mueq/min, and urinary chloride excretion (UClV) of 848 mueq/min during nitrate loading compared with an increase in CNa/GFR of 37.6%, UNaV of 2,362 mueq/min, and UClV of 2,397 mueq/min during saline loading. The smaller diuretic-induced increment in Na and Cl excretion in the nitrate studies suggests, as do the hydrated studies, that less Cl and Na are reabsorbed in the distal nephron during nitrate than saline loading. At every level of UNaV, fractional bicarbonate reabsorption was higher, urine pH was lower, and urinary potassium excretion (UKV) was higher in the nitrate studies. Thus, compared with saline loading, sodium nitrate decreases chloride and sodium reabsorption in the distal nephron. The higher hydrogen and potassium secretion in the nitrate studies may be consequent to the decreased ability of the distal nephron to reabsorb chloride.