Dietary Tyrosine Protects Striatal Dopamine Receptors from the Adverse Effects of REM Sleep Deprivation

L-Tyrosine is a non-essential amino acid that is produced as an intermediary metabolite in the conversion of phenylalanine to 3,4-dihyroxyphenylalanine (DOPA), and is a precursor of the neurotransmitter dopamine. In previous studies, tyrosine pretreatment was shown to protect against the neurochemical and behavioral deficits of acute stress caused by tail shock or cold exposure in rodents. The present study addressed the hypothesis that tyrosine administration may be an effective counter-measure to dopamine-mediated behaviors induced by rapid eye-movement sleep deprivation (RSD). In order to test the hypothesis, Sprague-Dawley rats were divided into 9 treatment groups: RSD-treated rats on normal-protein diet (20% casein: 1% tyrosine, 1% valine); tank control (TC) rats on a normal diet; cage control (CC) rats on normal diet; RSD-treated rats on 4% tyrosine diet; TC rats on 4% tyrosine diet; CC rats on 4% tyrosine diet; RSD-treated rats on 4% valine diet; TC rats on 4% valine diet; CC rats on 4% valine diet. In the RSD group receiving tyrosine, there was no apparent change in Bmax for binding of the dopamine D2 receptor ligand [(3)H]YM-09151-2 in the striata as compared to the respective TC and CC groups; whereas RSD-treated rats maintained on the normal diet and valine supplementation demonstrated expected increases in Bmax for ligand binding. The TC group on the tyrosine diet showed attenuated catalepsy compared to the corresponding CC group, while the RSD group consuming tyrosine showed a catalepsy that was significantly increased, and similar to that of cage control animais on a control diet. These data suggest that the tyrosine-supplemented diet significantly attenuated RSD-induced changes in striatal dopamine D2 receptors, and the effect appeared sufficient to influence RSD-induced behaviors.

Genital malformations and coexistent urinary tract or spinal anomalies in patients with imperforate anus

PURPOSE

Urinary tract malformations have been described in up to 50% of patients with imperforate anus but genital anomalies have been less well analyzed in the same patient population. We sought to evaluate the frequency of coexisting genital, urinary and spinal malformations in a population with imperforate anus.

MATERIALS AND METHODS

We reviewed 128 cases of imperforate anus, focusing on genital malformations and their relationship to anomalies of the urinary tract and spine. The series included 69 boys and 59 girls with low (59), intermediate (22) and high (47) imperforate anus.

RESULTS

Boys were much more likely to have a genital or upper urinary tract problem than girls (26 or 50 versus 5 or 30%, respectively). The risk for both sets of problems increased with the level of the anorectal lesion. The incidence of genital malformations increased from 14 to 26% in the presence of a renal lesion and from 10 to 23% with an associated spinal problem. Conversely, the incidence of urinary and spinal anomalies increased in patients with genital malformations.

CONCLUSIONS

The genitalia of children with imperforate anus should be carefully examined. Patients with anorectal malformations should also be evaluated for urinary tract and spinal problems. The yield of such studies increases in patients with recognized genital malformations.

Clinical care pathway for the management of ureteroneocystostomy in the pediatric urology population

PURPOSE

The management of vesicoureteral reflux continues to evolve. Endoscopic and laparoscopic techniques have been reported as alternatives to standard surgical techniques. However, the newer modalities have no long-term track record and there is some question as to efficacy. We sought to establish a clinical care pathway for managing ureteroneocystostomy in children.

MATERIALS AND METHODS

In the last 4 years we have developed a management technique based on a clinical collaborative care pathway with the help of surgeon, house staff, clinical nurse specialist and support personnel, that is floor, operating room and post-anesthesia nurses. The pathway includes extensive preoperative parent and child education, standard intraoperative management and postoperative care without catheter drainage. It is based on a postoperative hospital stay of 2 days without a ureteral or urethral catheter. We report on the care of 110 consecutive patients (190 ureters) who underwent simple or common sheath ureteroneocystostomy from April 1992 to July 1996.

RESULTS

No patient required the use of a urethral catheter or ureteral stent. Average length of hospital stay was 2.8 days and there were no immediate postoperative complications. At an average followup of 26 months (range 5 to 53) an overall success rate of 97% per patient and 98% per ureter was achieved. Analysis of the costs of simple and common sheath ureteroneocystostomy in the clinical care pathway revealed a 4% increase over those in an ideal case with no deviations from the pathway. Costs and length of hospital stay were then compared to those for institutions of the university hospital consortium and they were found to be 39 and 45% less, respectively. Outcome based analysis by telephone interview revealed 100% patient or parent satisfaction.

CONCLUSIONS

We believe that the management of vesicoureteral reflux using a coordinated clinical care pathway significantly improves length of hospitalization and inpatient costs with a high satisfaction score from parents and patients. This health care delivery style provides a standard to which other vesicoureteral reflux procedures must be compared.

Potential risk factors associated with progressive renal damage in childhood urological diseases: the role of angiotensin-converting enzyme gene polymorphism

PURPOSE

Experimental as well as human studies have established an important role for the renin-angiotensin system in the progressive deterioration of renal function. Recently genetic polymorphism in components of the renin-angiotensin system has been associated with several cardiovascular diseases, particularly variations in the angiotensin-converting enzyme gene that involve insertion (I) or deletion (D) of a 287 bp fragment. The D variant has been associated with myocardial infarction and cardiac hypertrophy.

MATERIALS AND METHODS

To assess whether this genetic variant is associated with worse prognosis in renal disorders we evaluated 70 children with congenital urological abnormalities, since a substantial number have progressive renal deterioration even after early corrective intervention. Renal deterioration was assessed by the presence or absence of radiographic evidence of parenchymal damage and serum creatinine.

RESULTS

Among patients with no radiographic renal parenchymal damage angiotensin-converting enzyme genotype distribution of II, ID and DD was 24, 67 and 9%, respectively. In contrast, a significantly different angiotensin-converting enzyme genotype distribution was observed in patients with evidence of parenchymal damage, that is 10, 49 and 41% for II, ID and DD, respectively (p < 0.05, chi-square 5.0). Mean serum creatinine plus or minus standard error in the former group was normal at 0.6 +/- 0.1 mg./dl., while in those with scarring it was elevated at 1.1 +/- 0.1 mg./dl., as expected. In patients with the DD genotype an overwhelming frequency of parenchymal damage was observed, that is of all 22 with that genotype 20 (91%) had parenchymal damage.

CONCLUSIONS

Considered together, these studies suggest that there are differences in the distribution of angiotensin-converting enzyme gene polymorphism in patients with congenital urological abnormalities who have evidence of renal parenchymal damage versus those who do not have such damage. Given that this genetic variation activates the renin-angiotensin system and this activation may be particularly robust in the kidney, we propose that the genotype of an individual independent of other factors modifies the likelihood of parenchymal loss in this setting.

A nested case-control study of non-Hodgkin lymphoma and serum organochlorine residues

BACKGROUND

The steady worldwide increase in the incidence of non-Hodgkin lymphoma during the past few decades remains mostly unexplained. Several studies suggest that there may be an association between the agricultural use of the organochlorine 1,1,1-trichloro-2,2'bis(p-chlorophenyl)ethane (DDT) and increased risk of non-Hodgkin lymphoma. We have investigated the association between risk of non-Hodgkin lymphoma and body burden of selected organochlorines in the general population in a nested case-control study.

METHODS

We measured prediagnostic serum concentrations of DDT, its metabolites, and other organochlorines, including polychlorinated biphenyls (PCBs), in 74 cases of non-Hodgkin lymphoma and 147 matched controls identified from a prospective cohort of 25,802 adults, established in 1974 in Washington County, Maryland, USA. We report results for total lipid-corrected serum concentrations of DDT and total PCBs.

FINDINGS

There was a strong dose-response relation between quartiles of total lipid-corrected serum PCB concentrations and risk of non-Hodgkin lymphoma overall (odds ratios by quartile: 1.0; 1.3 [95% CI 0.5-3.3]; 2.8 [1.1-7.6]); and 4.5 [1.7-12.0]; p for trend = 0.0008) and separately in men and in women. There was also evidence suggesting that seropositivity for the Epstein-Barr virus early antigen potentiated the effects of serum PCBs. By contrast, total lipid-corrected serum concentrations of DDT were not associated with risk of non-Hodgkin lymphoma.

INTERPRETATION

These results should be regarded as hypothesis-generating. Before causal inferences can be made about exposure to PCBs and increased risk of non-Hodgkin lymphoma, our findings require replication and the biological plausibility of the association needs further investigation.

Evaluation of renal resistive index, maximum velocity, and mean arterial flow velocity in a hydronephrotic partially obstructed pig model

RATIONALE AND OBJECTIVES

The authors investigate, in a controlled pig model, the usefulness of Doppler sonographic measurements of resistive index (RI), maximum velocity (Vmax), and mean velocity (Vmean) in diagnostic evaluation of the partially obstructed kidney.

METHODS

Seven female pigs underwent surgical partial unilateral renal obstruction at the ureteropelvic junction. Doppler parameters of RI, Vmax, and Vmean were measured preoperatively and postoperatively in obstructed and contralateral nonobstructed kidneys. The General Linear Model multivariate analysis of variance was used for statistical analysis of data.

RESULTS

There was no significant difference in the preoperative control values of RI (P = 0.71), Vmax (P = 0.27), and Vmean (P = 0.12). There was a statistically significant decrease in the Vmax and Vmean after postoperative day 5 in the obstructed kidney compared with the contralateral nonobstructed kidney (P = 0.01 and 0.03, respectively). There was no statistically significant difference in RI during the study.

CONCLUSIONS

In this study, RI was not a reliable indicator of partial renal obstruction. Measurements of maximal and mean blood flow velocities reached discriminatory significance only after the fifth postobstructive day, proving insensitive in the immediate postobstructive period. Vmax and Vmean demonstrated a decrease in the partially obstructed renal collecting system after 5 days of obstruction and may serve as useful parameters in the evaluation of obstruction after the immediate acute period, when compared with a nonobstructed contralateral system.

An improved analysis for chlorinated pesticides and polychlorinated biphenyls (PCBs) in human and bovine sera using solid-phase extraction

Chlorinated pesticides and polychlorinated biphenyls (PCBs) remain public health concerns because of their unresolved health impact and their persistence in humans. Current epidemiological studies of cancer, non-Hodgkins lymphoma, and endocrine disruption in National Center for Environmental Health (NCEH) laboratories require exposure assessment of many analytes in thousands of people. Previous methods of analyzing pesticides and PCBs in serum have proven inadequate for timely processing of the number of samples required for epidemiological studies. A new method that involves solid-phase extraction (SPE) and cleanup followed by dual-column gas chromatographic separation and electron capture detection has been developed. Nine surrogate compounds were added to the serum prior to sample workup to provide quality assurance for the SPE steps. These surrogates mimic the chemistry of the analytes in the extraction, cleanup, and gas chromatographic analysis steps. To increase selectivity, extracts were injected onto two gas chromatographs with different capillary columns, a DB-1701 and a DB-5. Recoveries of 17 pesticides, 28 PCB congeners, and one polybrominated biphenyl congener ranged from 40 to 80%. Recoveries from this procedure were found to be similar to those from the previously used liquid-liquid extraction method. Correlation of analyte and surrogate recoveries were compared to examine the ruggedness of the technique. The SPE method was found to provide improved sample throughput by a factor of 15.

Preclinical experiences with magnetic drug targeting: tolerance and efficacy

Although site-specific direction of drugs within an organism would benefit patients with many diseases, active drug targeting is clinically not yet possible. To overcome some of the problems associated with active drug targeting, we have developed a magnetic fluid to which drugs, cytokines, and other molecules can be chemically bound to enable those agents to be directed within an organism by high-energy magnetic fields. In the first part of this study, various concentrations of the magnetic fluid were tested in rats and immunosuppressed nude mice with regard to subjective and objective tolerance. In the second part, the same parameters were evaluated after administration of the ferrofluid to which epirubicin (4'-epidoxorubicin) was chemically bound. Finally, two forms of therapy with the magnetic fluid were tested: tumor treatment by mechanical occlusion with the ferrofluid in high concentrations; and magnetic drug targeting, using small amounts of the ferrofluid as a vehicle to concentrate epirubicin locally in tumors. As a result, the ferrofluid did not cause major laboratory abnormalities; there was no LD50. With very high concentrations of the ferrofluid, animals showed lethargy for 1-2 days. There were no intolerances with the epirubicin-bound ferrofluid as well. Both forms of treatment led to complete tumor responses in an experimental human kidney as well as in a xenotransplanted colon carcinoma model. Thus, the magnetic fluid is a safe agent, which can be used in different ways for local forms of cancer treatment in conjunction with high-energy magnetic fields.

Laparoscopic evaluation for contralateral patent processus vaginalis: Part II

Between May 1,1992 and August 1, 1995, 599 consecutively treated children under 10 years of age evaluated by the authors for a known inguinal hernia were involved in a prospective protocol to determine whether diagnostic laparoscopy has a place for evaluation of the contralateral inguinal region. The experience with the first 221 patients was reported at the 1993 AAP meeting. In this total experience, 81 patients had known bilateral inguinal hernias and did not require diagnostic laparoscopy. Five hundred eighteen patients had a unilateral inguinal hernia with the status of the contralateral region being unknown. Between May 1, 1992 and May 1, 1994, 368 children underwent evaluation using an umbilical approach. However, for the past 14 months, 150 patients have undergone the diagnostic laparoscopy through the ipsilateral hernia sac. Among the children under 1 year of age, 98 were found to have a unilateral hernia and also a contralateral patent processus vaginalis (CPPV) and 110 had a unilateral hernia. Of the children older than age 1,116 had a unilateral hernia and CPPV and 194 had only a single hernia. After induction of anesthesia, it was suspected on clinical examination that 195 of the 518 patients had a CPPV. However, laparoscopy showed that only 94 (48%) had a CPPV. In the remaining 323 patients, the surgeon believed that a CPPV was not present based on the examination. This negative finding was verified in only 198 patients (81%), but a surprising 125 (39%) did have CPPV documented at the time of endoscopy. Insufflation alone was very unrellable for documenting the presence of CPPV. Of the 214 patients for whom CPPV on the contralateral side was documented during laparoscopy, only 41 (19%) had a positive finding on insufflation. This experience has convinced the authors that diagnostic laparoscopy is the most accurate means to ascertain whether a patient should undergo contralateral inguinal exploration. In addition, laparoscopy through the ipsilateral inguinal sac is now the preferred approach.

The value of Doppler resistive index and peak systolic velocity in the evaluation of porcine renal obstruction

PURPOSE

We evaluated the use of Doppler resistive indexes and systolic velocities as diagnostic tools in a partially obstructed animal model.

MATERIALS AND METHODS

We studied 12 normal pigs by Doppler sonography, which served as control units. In 9 subjects partial ureteral obstruction was then created surgically, and 3 continued as controls. The presence or absence of obstruction was confirmed by ultrasound, antegrade nephrostography and intrapelvic pressure monitoring. Doppler parameters were measured 1 hour to 21 days postoperatively. Resistive index, and angle corrected peak and mean systolic velocities were measured bilaterally from samplings of interlobar and arcuate arteries. An average of 4 samplings per kidney was obtained at each session. Data from the control and obstruction groups were compared for statistical differences.

RESULTS

In controls mean resistive index was 0.53, and peak and mean systolic velocities were 0.38 and 0.26 m. per second, respectively. In the subacute period after obstruction (defined as days 4 to 21) mean resistive index was 0.54, and peak and mean systolic velocities were 0.33 and 0.22 m. per second, respectively. Compared to control data there was no significant change in resistive index after obstruction (p = 0.6). However, peak and mean systolic velocities showed significant downward trends (p < 0.05).

CONCLUSIONS

Known small sequential changes in renal blood flow after ureteral obstruction are reflected in flow velocities, as measured by duplex Doppler sonography. However, resistive indexes are not useful in assessing these changes in renal blood flow, and they do not correlate with the presence or absence of obstruction in this animal model.

The natural history of nephrocalcinosis in premature infants treated with loop diuretics

PURPOSE

We investigated the natural history of nephrocalcinosis in premature infants treated with furosemide and attempted to identify factors to predict infants most at risk.

MATERIALS AND METHODS

We evaluated 13 preterm infants in this longitudinal pilot study. During hospitalization and while receiving a loop diuretic nephrocalcinosis developed in each patient. Patients were divided into groups based on resolution (6) and nonresolution (7) according to spontaneous resolution of nephrocalcinosis at any point during followup. The 2 groups were compared to each other and to a control group.

RESULTS

Mean followup after discontinuation of furosemide in the resolution versus nonresolution groups was 10.3 and 7.7 months, respectively. Between the 2 groups there was no significant difference in average gestational age, birth weight, number of days hospitalized or on furosemide, or total furosemide dose. Mean calcium-to-creatinine ratio while receiving furosemide at the time nephrocalcinosis developed was 0.38 in the resolution group but 2.23 in the nonresolution group (p < 0.005). Initial calcium-to-creatinine ratio in age matched infants who did not have nephrocalcinosis was 0.4. Frank renal stones developed in 2 of the 7 patients without resolution and 0 of the 6 with resolution. When nephrocalcinosis resolved, it was at a mean of 5.2 months following discontinuation of the diuretic.

CONCLUSIONS

Early data indicate that nephrocalcinosis resolves in approximately 50% of premature infants 5 to 6 months after discontinuation of furosemide. The only factor that appears to be predictive of the infants who will have resolution is the calcium-to-creatinine ratio when nephrocalcinosis is diagnosed. In patients without resolution this ratio is much higher than in age adjusted normal controls, while in those with resolution it appears normal for age.

Penile orthoplasty using dermal grafts in the outpatient setting

OBJECTIVES

To review and evaluate our extensive outpatient experience in the use of dermal grafts for the correction of significant residual chordee in patients requiring penile orthoplasty.

METHODS

The medical records of all patients requiring surgical correction for severe penile curvature over the past 5 years were reviewed. Among these, 51 patients were identified in whom dermal grafts were used to correct severe residual chordee. Of these patients, 41 had severe hypospadias, 9 had epispadias, and 1 had urethral atresia. Graft harvest and placement technique, any resulting complications, and parental satisfaction with cosmetic and functional results were all evaluated.

RESULTS

The dermal grafts were harvested from the hairless skin of the inguinal area, using one of two techniques. All were used to fill a tunical defect created by incising the tunica at the point of maximal penile curvature. No complications or postoperative hospitalizations resulted from any of the orthoplasty procedures. At a mean follow-up of 27 months, all patients had excellent cosmetic and functional results.

CONCLUSIONS

In patients with significant residual chordee, a dermal graft is our preferred method of penile orthoplasty. This technique provides a straight phallus with a very minimal complication rate, it can easily and successfully be performed as an outpatient procedure, and it has assured an excellent cosmetic and functional result.

Unilateral hydronephrosis in infants: are measurements of contralateral renal length useful?

PURPOSE

We investigated whether measurement of contralateral renal length in newborns with unilateral hydronephrosis may help to assess clinically significant hydronephrosis in the affected kidney.

MATERIALS AND METHODS

We reviewed our experience with 53 newborns who had unilateral hydronephrosis presumed secondary to ureteropelvic junction obstruction. We divided the patients according to the presence of mild hydronephrosis and no obstruction on a furosemide renogram, severe hydronephrosis and obstruction on a furosemide renogram or a unilateral multicystic kidney.

RESULTS

We found no significant correlation between findings on the affected and opposite normal sides. Contralateral hypertrophy, hypotrophy and normal sized kidneys were frequent findings.

CONCLUSIONS

We conclude that measurement of contralateral renal length is not helpful in the evaluation of newborns with unilateral hydronephrosis.

Changes in monoamines and their metabolite concentrations in REM sleep-deprived rat forebrain nuclei

Rapid eye movement sleep deprivation (REMSD) is a potent stressor in rats. Behavioral abnormalities such as passive and active avoidance, locomotor activity, problem solving, sensory information processing, and the development of adaptive copping strategy in response to repeated stress are among the earliest obvious symptoms of REMSD, the mechanism for which remain largely unknown. The aim of this study was to determine whether 96 h of REMSD causes changes in monoamine neurotransmitters concentrations in rat forebrain regions (frontal cortex, FC; parietal cortex, PC, and striatum) that are involved in mediating higher brain functions such as attentional mechanisms, sensory information processing, and locomotor activity, which are severely affected in REMSD conditions. Rats were subjected to 96 h of REMSD using inverted flower pot water tank technique. To account for the stress associated with water tanks, a tank control group (TC) was included where the animals could reside comfortably on a large pedestal in the water tank. Regional brain concentrations of norepinephrine (NE), dopamine (DA), dihydroxyphenyacetic acid (DOPAC), L-3,4-dihydroxyphenylalanine (L-DOPA), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (HIAA) were determined by electrochemical detection using high-performance liquid chromatography. The concentrations of serotonin and its metabolite, HIAA, was reduced in the frontal and parietal cortexes of REMSD rats compared with TC or cage control (CC) group. NE, DA, DOPAC, and HVA concentrations in FC and PC of REMSD animals were remained unchanged compared with TC or CC rats. A significant increase in the concentrations of DA metabolites was observed in the striatum of REMSD rats when compared with CC and TC rats. There was a 29 and 31% increase in the concentration of striatal DA in REMSD group compared to the TC and CC groups, respectively; however, these percentages were not statistically different. Striatal NE, 5-HT, and HIAA concentrations were not significantly different among the three groups. These results suggest that 96 h of REMSD alters dopaminergic and serotonergic systems in different locations in rat brain. The effect of REMSD on the serotonergic systems are localized in the cerebral cortex, whereas dopaminergic metabolism is increased in the striatum.

Selected analytical methods used at the Centers for Disease Control and Prevention for measuring environmental pollutants in serum

Blood serum is one of the more viable matrices used in assessing exposure to persistent environmental contaminants or their metabolites, especially those that are lipophilic. Analytic methods currently in use for this matrix usually involve liquid/liquid extraction followed by adsorption chromatography as a cleanup step, and low- or high-resolution gas chromatography with either electron-capture or mass spectrometric detection. The traditional analytic methods are labor intensive, have low sample throughput, and use excessive amounts of solvents and reagents. Two analytic approaches that address the requirements of modern laboratories more effectively are: 1) solid-phase extraction (SPE), used to analyze serum for several classes of compounds of environmental concern (e.g., polychlorinated biphenyls [PCBs], persistent pesticides, dioxins, furans, and coplanar polychlorinated biphenyls [CPCBs]), and 2) fast chromatography with a two-dimensional gas chromatographic system, which can be used in the determinative step for these types of analytes.

A rat homolog of the mouse deafness mutant jerker (je)

An autosomal recessive deafness mutant was discovered in our colony of Zucker (ZUC) rats. These mutants behave like shaker-waltzer deafness mutants, and their inner ear pathology classifies them among neuroepithelial degeneration type of deafness mutants. To determine whether this rat deafness mutation (-) defines a unique locus or one that has been previously described, we mapped its chromosomal location. F2 progeny of (Pbrc:ZUC x BN/Crl) A/a B/b H/h +/- F1 rats were scored for coat color and behavioral phenotypes. Segregation analysis indicated that the deafness locus might be loosely linked with B on rat Chromosome (Chr) 5 (RNO5). Therefore, 40 -/- rats were scored for BN and ZUC alleles at four additional loci, D5Mit11, D5Mit13, Oprd1, and Gnb1, known to map to RNO5 or its homolog, mouse Chr 4 (MMU4). Linkage analysis established the gene order (cM distance) as D5Mit11-(19.3)-B-(17.9)-D5Mit13-(19. 2)-Oprd1-(21.5) - (1.2) Gnb1, placing the deafness locus on distal RNO5. The position of the deafness locus on RNO5 is similar to that ofjerker (je) on MMU4; the phenotypes and patterns of inheritance of the deafness mutation and je are also similar. It seems likely that the mutation affects the rat homolog of je. The rat deafness locus should, therefore, be named jerker and assigned the gene symbol Je.

Abnormal behaviors in the stargazer rat are maladaptive, but not anxiety related

The stargazer rat is an autosomal recessive mutant (homozygous stg/stg) that displays abnormal behavior, including profound hyperactivity. Heterozygous stg/+ littermates are unaffected (i.e., are nonmutants), and display normal spontaneous behaviors. Abnormal spontaneous behavior in the stargazer rats suggest that they may be more responsive than their normal littermates to external stimuli and more likely to display anxiety-related behavior in tests of emotionality. To test these hypotheses, the reactive behavior of stargazers and unaffected littermates were compared with regard to their responsiveness to nociceptive stimuli (tail flick test), in the open field test, the elevated plus-maze, and in the swim test of Porsolt. In the open field test, the stargazers spent a greater percentage of the observation period in the open area (p < 0.05), and demonstrated a significantly higher level of locomotor activity (p < 0.05). In the elevated plus-maze, stargazers spent a significantly greater percentage of their total time in the open arms (p < 0.05), but the number of open-arm entries as a percentage of total entries into either arm was not different among the two groups. The stargazers were unable to complete the Porsolt test, perhaps owing to their being ineffective swimmers. No differences among the groups were observed with the tail flick test. Contrary to the original hypothesis, these data suggest that the mutant rats demonstrated less anxiety-related behavior than their nonmutants siblings in tests of emotionality.

The use of laparoscopy in the management of the nonpalpable testis

Fifty-eight children with a nonpalpable testis have been evaluated at our institution between 1988 and 1994. Laparoscopy was performed in these children to effect a treatment plan. The children range in age from 10 months to 14 years. Thirty patients had a nonpalpable left testis, 18 had a nonpalpable right testis, and 10 had bilateral nonpalpable testes. In 28 children, a testis was visualized. Two underwent laparoscopic orchiectomy and 26 underwent either a standard single stage procedure (11), a staged open procedure (3), or a laparoscopically assisted staged procedure (12). Attenuated vessels were seen in 26 patients and inguinal exploration revealed a viable testis in 6 patients and a testis remnant, which was removed, in 20 patients. Four patients had laparoscopic blind-ending vessels. Diagnostic laparoscopy affords the surgeon not only the ability to localize the testis with virtual certainty, but also the advantage of planning a highly successful treatment program. The position of the testis intra-abdominally and the length of the spermatic vessels can be easily evaluated to decide whether a staged approach versus a single stage procedure can be performed. The use of the KTP laser has made the two staged procedure quite easy with only one Trocar site necessary. This experience has allowed us to develop and modify an algorithm for the effective management of the nonpalpable testis.

Continuous caudal anaesthesia with chloroprocaine as an adjunct to general anaesthesia in neonates

PURPOSE

The authors prospectively evaluated the use of a continuous caudal epidural infusion of chloroprocaine as an adjunct to general anaesthesia during intra-abdominal surgery in neonates.

CLINICAL FEATURES

The technique was used in 25 neonates ranging in age from 1 to 28 days and in weight from 2.2 to 4.9 kg. Following anaesthetic induction and tracheal intubation, an initial bolus dose of chloroprocaine 3% (1 or 1.5 ml.kg-1) was followed by a continuous infusion of 1 or 1.5 ml.kg-1.hr-1 administered through a caudal epidural catheter. No parenteral opioids were administered. The duration of the surgical procedures varied from one hour five minutes to three hours 15 min. The first three neonates received a bolus dose of 1.0 ml.kg-1 followed by an infusion of 1.0 ml.kg-1.hr-1 chloroprocaine 3%. These three neonates required an additional bolus dose followed by an increase in the infusion to 1.5 ml.kg-1.hr-1 to provide surgical anaesthesia. Adequate intraoperative anaesthesia was achieved in all 25 neonates with an infusion of 1.5 ml.kg-1.hr-1 of chloroprocaine 3%. This was evidenced by a lack of haemodynamic response to surgical manipulation. No neonate required more than 0.2% isoflurane or 70% nitrous oxide in oxygen. No episodes of haemodynamic instability (decreased blood pressure/bradycardia) related to the caudal epidural anaesthesia were noted. Twenty-three of 25 of the neonates' tracheas were extubated immediately (within 10 minutes) following the surgical procedure.

CONCLUSIONS

Caudal anaesthesia with a continuous infusion of chloroprocaine can be used as an adjunct to general anaesthesia during abdominal surgery in neonates. Our initial experience suggests that the combined technique may eliminate the need for parenteral opioids and limit the intraoperative requirements for inhalational anaesthetic agents.

Isolated ureteral injury caused by blunt trauma

OBJECTIVES

Ureteral injury is rare after blunt trauma. Herein is presented this unusual scenario of ureteral trauma in addition to the pathophysiology of this injury.

METHODS

A 12-year-old boy sustained a rupture of the right ureter 6 cm below the ureteropelvic junction after a car accident. No other injuries or fractures were identified.

RESULTS

Ureteral injury was immediately diagnosed and repaired primarily. Intravenous urography performed 8 weeks after surgery revealed normal ureteral healing without stricture formation.

CONCLUSIONS

To our knowledge, the isolated avulsion of the ureter in this location has not been reported previously, but must be considered in those patients with severe blunt trauma and hyperextension injuries.

Evidence for genetically mediated dysfunction of the central dopaminergic system in the stargazer rat

The stargazer rat is an autosomal recessive mutant (homozygous stg/stg) that displays abnormal behavior, characterized by stereotypic head-movement, circling, and a high level of ambulatory activity. Heterozygous (stg/+) littermates display normal spontaneous behaviors. In this study, stargazers and their unaffected littermates were compared in their behavioral responses to both stimulation and inhibition of dopamine D2/D3 receptors, using quinpirole and haloperidol. Stargazers were observed to yawn a significantly fewer number of times than littermates in response to (--)-quinpirole (50 mu g/kg, IP). Haloperidol (HAL 0.1 mg/kg and 0.3 mg/kg, SC) caused a decrease in stereotypic head-movement in the mutants that was both time- and dose-dependent. In normal littermates, HAL inhibited locomotor activity and produced catalepsy in a time- and dose-dependent manner. In stargazers, both doses of HAL inhibited locomotor activity to a similar degree as in the littermates. However, no catalepsy was detectable in the mutants using 0.1 mg/kg of HAL. A dose of 0.3 mg/kg HAL was only weakly cataleptogenic. Overall, the spectrum of abnormal behaviors expressed by the stargazers and the present evidence of D2/D3 receptor subsensitivity suggest that stargazers possess a genetically mediated dysfunction of the central dopaminergic system.

A paradoxical elevation of brain cyclo(His-Pro) levels in hyperphagic obese Zucker rats

Several studies suggest a role for endogenous cyclo(His-Pro) or CHP in appetite regulation. In the present study, we have examined the regional brain distribution of CHP in hyperphagic obese Zucker rats and their lean littermates. The data show a significant elevation in the levels of CHP in many brain regions, including hypothalamus of the obese rat. Within the hypothalamus, the lateral hypothalamic (LH) nucleus of obese rats had significantly higher levels of CHP when compared to that of the lean littermates. Administration of dehydroepiandrosterone, a steroid hormone known to decrease food intake and body weight gain, to obese rats led to decrease in the levels of CHP in the LH. These data further suggest a role for the endogenous CHP in attenuating food intake.

REM sleep deprivation alters dopamine D2 receptor binding in the rat frontal cortex

REM sleep deprivation (RSD) of rats results in facilitation of dopaminergic behavior and an increase in striatal D2 receptor density. To determine whether RSD results in changes in D2 receptor in other brain regions, receptor affinity (Kd) and density (Bmax) were measured in the anteromediofrontal (AM), cingulate (CN), and sulcal cortex (SL) in four groups of rats: 1), RSD96 group (RSD for 96 h; small pedestal/water tank method), 2) RSD24 group (large pedestals for 72 h then small pedestals for 24 h), 3) tank control group (TC; large pedestals for 96 h), and 4) cage control group. In separate groups, ambulation was recorded for 30 min following treatments. Group RSD96 showed an increase in activity compared to TC, and TC was increased compared to CC (p < 0.05 for all). In group RSD24, the AM showed an increase in Bmax and Kd (p < 0.05), but there were no effects by RSD96. In the CN, Bmax and Kd were decreased by RSD96 (p < 0.05) but not RSD24. In the SL, Bmax was increased by RSD96, but not RSD24, whereas Kd was increased in both RSD groups (p < 0.05).