Biomedical subjects

J Roth

Publications and source records attributed to J Roth.

At least 37 records · Page 2Linked to original sources

PubMed1992

Characterization of soluble neural cell adhesion molecule in rat brain, CSF, and plasma.

The polypeptide composition and glycosylation of soluble isoforms of neural cell adhesion molecule (NCAM) in developing rat brain, CSF, and plasma were characterized. Soluble NCAM in rat brain consisted of several glycosylated isoforms. The degree of glycosylation was developmentally regulated. After desialylation, four polypeptides of M(r) values of approximately 190,000 (s1), 135,000 (s2), 115,000 (s3), and 110,000 (s4) were observed. Polypeptides s1, s2, and s3 were also present in CSF, whereas only s3 and s4 were observed in plasma. Treatment of soluble brain NCAM with N-glycosidase F, which removes N-linked carbohydrates, produced polypeptides of M(r) values of approximately 190,000, 125,000, and 108,000-97,000. The monoclonal antibody OB11, which recognizes an epitope on the cytoplasmic part of transmembrane forms of NCAM, did not react with any of the soluble isoforms. Purified soluble NCAM, consisting mainly of s3, contained an N-terminal sequence identical to that of membrane-associated NCAM. Gel filtration of s3 indicated that it was present as a dimer under the chosen conditions. NCAM-expressing glioma cells adhered specifically to immobilized soluble NCAM. This implies that functionally significant soluble forms of NCAM are present in the extracellular fluid.

Aging↗

PubMed1992

Programmed electrical stimulation protocols: variations on a theme.

A series of prospective protocols were designed to determine the yield ratio (true positives vs. false positives = nonclinical) in various patient groups using a variety of programmed electrical stimulation (PES) variables. First, a PES protocol was used in 772 patients. Single, double, and triple extrastimuli were delivered in sequence (leaving each successive extrastimulus just beyond its refractory period before moving to the next extrastimulus) during sinus rhythm and two ventricular paced rates at the RV apex, before moving to the outflow tract and repeating the sequence and then moving on to isoproterenol infusion with the PES sequence repeated at the apex. This protocol met NASPE standards for induction of VT in patients with coronary artery disease and a history of VT, while failing to induce monomorphic VT in any control patient. The best yield ratios combined with the greatest likelihood of inducing clinical tachycardia were achieved with sinus rhythm and three extrastimuli, and pacing at the lower rate and three extrastimuli. Pacing at the faster rate and triple extrastimuli was highly inductive of clinical arrhythmias, but had a low yield ratio due to induction of more nonclinical arrhythmias than other steps. The next protocol was performed in 61 patients with inducible ventricular tachycardia. In each case, the protocol described above was completed at the RV apex, even if tachycardia was also induced at an earlier point in the protocol. This allowed for more accurate yield ratios to be established for each step in the protocol, since each patient was exposed to each of these steps.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗

PubMed1992

Clinical evaluation of the safety of repetitive intraoperative defibrillation threshold testing.

One goal of the initial implantation procedure for a cardioverter defibrillator is determination of the configuration and patch location with the lowest defibrillation threshold (DFT). To determine the safety of multiple defibrillation tests, an analysis of the intraoperative defibrillation threshold tests (DFTT) in our patients was performed. In 84 patients, the mean number of DFT trials was 5.27; the mean number of joules received was 275.0. The maximum number of shocks in one implant procedure was 50 for a total of 4,895 joules without complications. Four patients received 30 or more DFT shocks without complication. There were two complications related directly to the DFTT: one patient with severe noninflammatory cardiomyopathy developed electromechanical dissociation and was subsequently resuscitated and survived; the second patient with severe triple vessel coronary artery disease suffered an intraoperative myocardial infarction during testing and eventually died 22 days postoperatively. All patients received an ICD unit; six patients had DFTs of greater than 20 joules. Based on our experience, we followed the clinical status (heart rate, blood pressure, ECG changes, fluid status, total anesthesia time) during the DFTT to determine the extent and duration of our testing protocol. Multiple shocks due to repositioning of the leads in a stable patient should not prohibit extensive testing as adverse consequences do not appear to be cumulative.

Electric Countershock↗

PubMed1992

Alteration of endotoxin fever and release of arginine vasopressin by dehydration in the guinea pig.

Arginine vasopressin (AVP), synthesized in hypothalamic neurons, is transported in axons either to the pituitary for release into the circulation or to different brain areas. In our previous experiments we documented central antipyretic AVP pathways from the hypothalamus to the ventrolateral septal area in the limbic system. In the present study we investigated if osmotic stimulation is able to activate peripheral and central release of AVP concurrently and if the antipyretic pathways are influenced by this kind of stimulation. In dehydrated animals (24 h water deprivation) the arterial blood plasma level of AVP doubled causing antidiuretic effects. Also the concentration of AVP in push-pull perfusates of the limbic septal area was significantly higher in dehydrated (5.6 pg AVP/ml perfusate) than in control animals (2.6 pg AVP/ml perfusate). The febrile response to bacterial endotoxin was reduced by 50% in dehydrated guinea pigs compared to controls, statistically significant between 30 and 180 min after pyrogen application. A microinfusion of AVP antiserum into the limbic septal area enhanced the fever reaction of dehydrated guinea pigs compared to the effects of a microinfused preimmune serum, in this case statistically significant between 180 and 360 min after application. From these data we assume a simultaneous activation of peripheral and central release of AVP with antidiuretic and antipyretic effects by dehydration.

Animals↗

PubMed1992

Expression of the calcium-binding proteins MRP8 and MRP14 by early infiltrating cells in experimental contact dermatitis.

The immune response to an allergen is not only dependent on the inflammatory stimulus, but also on the genetic disposition of the individual. Important effector cells in the immune response are myelomonocytic cells in their various differentiation stages. We recently described the expression of MRP8 and MRP14, two calcium-binding proteins of the S-100 family, by these cells during inflammatory activation. Here, we investigated whether their expression in murine contact dermatitis is dependent on the stimulus by which dermatitis is elicited, and if it is related to the genetic constitution of different inbred strains of mice. Therefore we performed immunohistochemical studies on the distribution of MRP8- and MRP14-positive cells during experimentally induced allergic (ACD) and irritant contact dermatitis (ICD). Both forms of dermatitis were elicited in BALB/c and C57B1/6 mice. BALB/c mice were found to react with a more intense inflammatory response in both ACD and ICD (high responders) than C57Bl/6 mice (low responders). The expression of MRP8 and MRP14 in both forms of dermatitis correlated with the early influx of macrophages and with the cell density of the infiltrate. Also the percentage of MRP8- and MRP14-positive cells in the infiltrate during ACD or ICD was higher in the more intense inflammatory reaction of BALB/c mice compared to C57Bl/6 mice. We conclude that MRP8 and MRP14 define a differentiation stage of inflammatory macrophages and that their expression correlates with the activity of inflammatory processes.

Animals↗

PubMed1992

Influence of left ventricular function on outcome of patients treated with implantable defibrillators.

BACKGROUND: The outcomes of patients treated with implantable defibrillators were compared between patients with left ventricular ejection fraction greater than or equal to 30% and less than 30%. METHODS AND RESULTS: Of 68 consecutive patients treated with implantable defibrillators, 40 patients (group 1) had left ventricular ejection fraction greater than or equal to 30%, and 28 patients (group 2) had left ventricular ejection fraction less than 30%. Sudden death, surgical mortality, nonsudden arrhythmia-related death (death within 24 hours after an arrhythmic event despite initial termination of the arrhythmia by the implantable defibrillator), total arrhythmia-related death (including sudden death, surgical death, and nonsudden arrhythmia-related death), and total cardiac death were compared between the two groups. Surgical mortality was 4.4% (0% in group 1, 11% in group 2). During the follow-up of 31 +/- 27 months, actuarial survival rates free of events were 97%, 97%, and 97% in group 1 and 96%, 91%, and 82% in group 2 at 12, 24, and 36 months, respectively, for sudden death (p = NS); 97%, 97%, and 97% in group 1 and 85%, 81%, and 72% in group 2 at 12, 24, and 36 months, respectively, for sudden death and surgical mortality (p less than 0.05); 97%, 97%, and 97% in group 1 and 82%, 78%, and 70% in group 2 at 12, 24, and 36 months, respectively, for total arrhythmia-related death (p less than 0.05); and 95%, 95%, and 95% in group 1 and 82%, 69%, and 57% in group 2 at 12, 24, and 36 months, respectively, for total cardiac death (p less than 0.05). Four (57%) of seven nonsudden cardiac deaths during the initial 36-month follow-up period were causally related to arrhythmia (three surgical deaths and one arrhythmia-related nonsudden death). CONCLUSIONS: The outcome of patients treated with implantable defibrillators is strongly influenced by the degree of left ventricular dysfunction. In group 1 patients, surgical mortality, sudden death, and total cardiac death are rare. In group 2, sudden death rate may not be markedly different from that of group 1 patients. However, the risk of therapy (surgical mortality) is high. Many nonsudden cardiac deaths are causally related to arrhythmia (surgical mortality or nonsudden arrhythmia-related death). Therefore, the survival rate free of total arrhythmia-related death is significantly lower in group 2 (70% versus 97% in group 1 at 3 years). Further studies are needed to determine the roles of defibrillator therapy and other therapies in various clinical settings.

Actuarial Analysis↗

PubMed1992

Glucose utilization in a patient with hepatoma and hypoglycemia. Assessment by a positron emission tomography.

Tumor glucose use in patients with non-islet-cell tumors has been difficult to measure, particularly in hepatoma, because of hepatic involvement by neoplasm. We studied a patient with nonhepatic recurrence of hepatoma after successful liver transplantation. Tumor tissue contained messenger RNA for insulin-like growth factor-II (IGF-II), and circulating high molecular weight components and E-peptide of IGF-II were increased. Glucose use measured by isotope dilution with [3-3H]glucose was 7.94 mg/kg fat-free mass per min, and splanchnic glucose production was 0.93 mg/kg fat-free mass per min. Glucose uptake and glucose model parameters were independently measured in tissues by positron emission tomography with 18F-fluoro-2-deoxy-D-glucose. Glucose uptake by heart muscle, liver, skeletal muscle, and neoplasm accounted for 0.8, 14, 44, and 15% of total glucose use, respectively. Model parameters in liver and neoplasm were not significantly different, and glucose transport and phosphorylation were twofold and fourfold greater than in muscle. This suggests that circulating IGF-II-like proteins are partial insulin agonists, and that hypoglycemia in hepatoma with IGF-II production is predominantly due to glucose uptake by skeletal muscle and suppression of glucose production.

Adult↗

PubMed1992

Detection of mutations in insulin receptor gene by denaturing gradient gel electrophoresis.

Denaturing gradient gel electrophoresis (DGGE) has been used to screen for mutations in the insulin receptor gene. Each of the 22 exons was amplified by the polymerase chain reaction (PCR). For each exon, one of the two PCR primers contained a guanine-cytosine (GC) clamp at its 5' end. The DNA was analyzed by electrophoresis through a polyacrylamide gel containing a gradient of denaturants. Two geometries for the gels were compared; the gradient of denaturants was oriented either parallel or perpendicular to the electric field. The sensitivity of the technique was evaluated by determining whether DGGE succeeded in detecting known mutations and polymorphisms in the insulin receptor gene. With parallel gels, 12 of 16 sequence variants were detected. The use of perpendicular gels increased the sensitivity of detection so that all 16 sequence variants were successfully detected when DNA was analyzed by a combination of perpendicular and parallel gels. Furthermore, DGGE was used to investigate a patient with leprechaunism whose insulin receptor genes had not previously been studied. Two mutant alleles were identified in this patient. The allele inherited from the father had a mutation substituting alanine for Val-28; in the allele inherited from the mother, arginine was substituted for Gly-366.

Alanine↗

PubMed1992

Studies on the Thomsen-Friedenreich antigen in human colon with the lectin Amaranthin. Normal and neoplastic epithelium express only cryptic T antigen.

The lectin Amaranthin has been shown to be highly specific for the galactose beta 1,3 N-acetylgalactosamine-alpha and sialic acid alpha 2,3 galactose beta 1,3 N-acetylgalactosamine-alpha sequence which represents the Thomsen-Friedenreich (T) antigen and its cryptic form, respectively. Previously, we demonstrated the usefulness of gold-labeled Amaranthin for the histochemical detection of the T antigen and its cryptic form. Application of the galactose oxidase (GO)-Schiff sequence abolished lectin binding to the T antigen but not its cryptic form, and therefore permitted their differentiation. In the present study we have analyzed by light and electron microscopy the distribution and subcellular localization of Amaranthin binding sites in normal, dysplastic and neoplastic colonic epithelium. Furthermore, a monoclonal antibody raised against synthetic galactose bera 1,3 N-acetylgalactosamine-alpha-bovine serum albumin was applied as a reagent for the T antigen. In normal colonic mucosa, two different Amaranthin staining patterns existed: (a) reactivity restricted to the lower portion of the crypts which was principally observed in the left colon, and (b) reactivity along the entire length of the crypts and in the surface epithelium with goblet cell staining in the upper portion of the crypts which was principally observed in the right colon. This Amaranthin staining was resistant to GO-Schiff treatment. No immunostaining with the monoclonal anti-T antigen was observed. Investigation of transitional mucosa, adenocarcinomas of different degrees of differentiation and mucinous carcinomas as well as adenomas with different degrees of dysplasia all revealed positive Amaranthin staining. The lectin staining was resistant to GO-Schiff treatment, and immunolabeling with the monoclonal antibody against the T antigen was absent. These results indicate that only the cryptic form of the T antigen is expressed in normal, dysplastic and neoplastic human colonic epithelium.

Antigens, Neoplasm↗

PubMed1992

[Charlin's syndrome--nasociliary nerve neuralgia].

The history, etiopathogenetical factors, clinical symptomatology, differential diagnosis and therapy of neuralgia nervi nasociliaris--Charlin's syndrome are described. The authors give an account of an 18-years-old male patient.

Adolescent↗

PubMed1992

Improved accuracy in diagnostic immunohistochemistry, lectin histochemistry and in situ hybridization using a gold-labeled horseradish peroxidase antibody and silver intensification.

BACKGROUND: Improvements in the use of the avidin-biotin peroxidase complex technique and direct as well as indirect labeled avidin-biotin methods for application in diagnostic immunohistochemistry, lectin histochemistry and in situ hybridization are reported. The new technology combines the advantages of immunoenzyme and immunogold silver staining techniques and can be performed on routinely fixed and paraffin-embedded tissues. EXPERIMENTAL DESIGN: The basic modification of the labeling procedures was introduced at the final revealing step. The histochemical visualization of catalytic activity of horseradish peroxidase by the diaminobenzidine reaction was replaced by the detection of horseradish peroxidase immunoreactivity using anti-horseradish peroxidase-gold complexes and their intensification with silver acetate which is relatively light insensitive. RESULTS: The use of gold-labeled anti-horseradish peroxidase antibodies eliminates the need for quenching of endogenous peroxidase activity. Furthermore, the immunogold silver staining provides improved lateral resolution, higher contrast, and lower background staining as compared with the diaminobenzidine reaction. The new technology has been applied for the localization of different polypeptides in endocrine cells, cytoskeletal elements, cell surface receptors, basal lamina type IV collagen, endothelial cell marker, lectin binding sites, and DNA of various viruses. CONCLUSIONS: We concluded that the anti-horseradish peroxidase-gold complex is of general use in a variety of techniques applying horseradish peroxidase as a marker and should be a valuable alternative to existing enzyme substrate techniques.

Gold↗

PubMed1992

Radiation therapy of acromegaly.

Conventional megavoltage irradiation of GH-secreting tumors has predictable effects on tumor mass, GH, and pituitary function. 1. Further growth of the tumor is prevented in more than 99% of patients, with only a fraction of a percent of patients requiring subsequent surgery for tumor mass effects. 2. GH falls predictably with time. By 2 years GH falls by about 50% from the baseline level, and by 5 years by about 75% from the baseline level. The initial GH elevation and the size and erosive features of the sella turcica do not affect the percent decrease in GH from the baseline elevation. 3. With prolonged follow-up, further decrease in GH is seen at 10 and 15 years, with the fraction of surviving patients achieving GH levels less than 5 ng/mL approaching 90% after 15 years in our experience. Gender, previous surgery, and hyperprolactinemia do not seem to affect the response to treatment. Patients with initial GH greater than 100 ng/mL are significantly less likely to achieve GH values less than 5 ng/mL during long-term follow-up. 4. Hypopituitarism is a predictable outcome of treatment, is delayed, and may be more likely in patients who have had surgery prior to irradiation. There is no evidence that this complication is more common in patients with acromegaly than in patients with other pituitary adenomas receiving similar treatment. 5. Vision loss due to megavoltage irradiation--using modern techniques and limiting the total dose to 4680 rad given in 25 fractions over 35 days, with individual fractions not exceeding 180 rad--is extremely rare. The reported cases have occurred almost entirely in patients who have received larger doses or higher fractional doses. The theory that patients with acromegaly are prone to radiation-induced injury to the CNS and optic nerves and chiasm because of small vessel disease is not supported by a review of the reported cases. 6. Brain necrosis and secondary neoplasms induced by irradiation are extremely rare. 7. Although anecdotal evidence raises the question of changes in intellectual function following irradiation, this has not been studied in adults receiving pituitary irradiation.

Acromegaly↗

PubMed1992

[Diagnostic problems in local recurrence after breast saving treatment].

353 patients with stages pTis, pT1-2, pN0-1, cM0 breast cancer have been treated consecutively by breast conserving therapy in a prospective, nonrandomized study at the University Hospital Basel and the Women's Clinic Rheinfelden/Baden/Germany. The median age was 47 years, the median follow-up time 67 months, and 4% only of this collective were lost to follow-up after a median time of 42 months. In 79% of the cases the tumor was excised totally, while in 19% the resection margins were positive and in 2% only the margins were not available for histological judgement. The rate of local failure reached 8% with a median time interval of 53 months. 116 patients showed postactinic induration in the primary tumor region. 73 of these were given additional diagnostic examination: The postactinic induration was judget clinically suspicious in 51 cases and clinically nonsuspicious of local failure in 22 cases. All 73 patients received additional examination by mammography and biopsy. By comparison with the histological results the clinical results were correct in 59% and false in 41%, while the mammographic results were correct in 82% and false in 18% of the cases.

Biopsy↗

PubMed1992

Evidence for antipyretic vasopressinergic pathways and their modulation by noradrenergic afferents.

The experimental evidence for the antipyretic action of arginine vasopressin (AVP) in guinea-pigs can be summarized as follows: The febrile response to a bacterial pyrogen can be reduced by a microinfusions of exogenous AVP into the ventral septal area of the limbic system. Immunohistochemical studies indicate increased activity of AVP terminals in the ventral septal area (VSA) and in parvocellular AVP neurones of the hypothalamic paraventricular nucleus (PVN) in several stressful situations accompanied by reduced febrile responses (late stage of pregnancy, immobilization, cold adaptation, osmotic stimulation). Also the peripheral and/or central release of AVP measured in some of these situations is increased. Electrical stimulation of the PVN suppresses fever, this suppression can, at least partly, be cancelled by simultaneous intraseptal application of the vasopressinergic V1 receptor antagonist. The documented AVP pathways from the PVN to the septum receive noradrenergic afferents from the lower brainstem. Chronic destruction of these afferents by microinjections of 6-hydroxydopamine (6-OHDA) significantly reduced the fever responses to pyrogen application, while microinfusion of noradrenaline (NA) enhances the fever reaction.

Afferent Pathways↗

PubMed1992

Educational outcome of neonatal intensive care graduates.

Studies of developmental outcome of neonatal intensive care unit graduates have generally been limited to the first 2 to 3 years of life, with outcome determined by psychometric tests. This study followed neonatal intensive care unit graduates born 1975 through 1983 (n = 457) into the public school system and compared their educational outcomes with those of newborn nursery graduates (n = 656). Outcomes were evaluated by placement in four academic categories: regular classroom, academic problems, speech/language impairment, and major impairment. Educational outcomes for children of both groups were essentially the same. Their placement in the four academic categories were equally affected by nonmedical variables, primarily income (below/above poverty level), race, and sex. Seventy percent of poverty-level children were in one of the three problem categories, compared with 40% of children above poverty level. Neither neonatal intensive care unit treatment nor low birth weight were major predictors of educational outcome. The only clear-cut neonatal intensive care unit effect occurred among children born with sensory or physical impairments. Therefore, in order to reduce poor educational outcomes, follow-up and intervention programs should be targeted primarily to children with diagnosable handicaps and from minority, low-income families.

Child↗

PubMed1991

DS28-6, a temperature-sensitive mutant of Chinese hamster ovary cells, expresses key phenotypic changes associated with brefeldin A treatment.

The temperature-sensitive Chinese hamster ovary (CHO) cell mutant DS28-6 has been previously shown to be pleiotropically defective in protein secretion. We have examined the mutant cells to determine the intracellular site of the block in secretion. By transmission electron microscopy a time-dependent disassembly of the Golgi apparatus was found under nonpermissive temperature, which resulted in the loss of the cisternal stack. Complete reorganization of the Golgi apparatus occurred after shift to permissive temperature. Under nonpermissive temperature, a microtubule- and energy-dependent redistribution of Golgi mannosidase II and galactosyltransferase into a pattern characteristic of the endoplasmic reticulum (ER) was observed. Inhibition of protein synthesis by cycloheximide had no influence on Golgi mannosidase II redistribution. Evidence for Golgi apparatus-associated processing of oligosaccharides in the ER was obtained by lectin-gold cytochemistry revealing the presence of the galactose (beta 1----4)N-acetylglucosamine sequence and sialic acid residues. Furthermore, 7-nitrobenz-2-oxa-1,3-diazol-4-yl-tagged ceramide, a lipidic trans-Golgi apparatus marker in CHO cells, exhibited an energy-dependent redistribution into the ER. These effects were fully reversible upon shift to permissive temperature. Thus, mutant DS28-6 cells exhibit key features of the brefeldin A phenotype, which suggests that the observed brefeldin A effects result from interference with a normally occurring cellular process.

Animals↗

PubMed1991

[Health status and late complications following allogeneic bone marrow transplantation. A review].

Better results following bone marrow transplantation (BMT) have increased the number of patients in longterm follow-up. Health status and late effects are therefore of increasing interest. We discuss here the incidence and follow-up of late complications after allogenic BMT. Any conditioning regimen including TBI in postpubertal women introduces a postmenopausal status. In contrast, normal function is found after BMT without irradiation. In men, there is usually permanent azoospermia after TBI but not following chemotherapy alone. Thyroid dysfunction after BMT with TBI has been reported in about 40% of patients. In most of them compensated hypothyroidism with elevated TSH is found. BMT with TBI induces growth retardation in children. Decreased growth hormone levels are observed and substitution can induce normal height development. Interstitial pneumonitis (IP) is a major cause of death. It occurs on average three months after BMT but late onset IP's are increasingly reported. Cataracts are common after BMT. The risk of cataracts in patients given single dose TBI attains 80-100% after four years. Under treatment with cyclophosphamide alone, the risk of lens opacification is less than 20%. So far, patients treated with fractionated TBI have not developed more cataracts than those treated with chemotherapy alone. Impaired renal function is common early post-transplant. Risk factors include cyclosporine (CSA) nephrotoxic antibiotics and antifungal drugs. So far, few secondary malignancies have been reported in humans after BMT. However, actual observation time is still too short for final evaluation. Prevention or treatment is instituted for common complications. It is expected that other types of tissue damage will be recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Two nonallelic insulin genes in Xenopus laevis are expressed differentially during neurulation in prepancreatic embryos.

Insulin, traditionally regarded as a metabolic hormone, also can potently stimulate growth and differentiation in many cell types. To study further the potential role of insulin during early embryogenesis, we have used the amphibian Xenopus laevis, a versatile model of vertebrate development. Using (i) nucleotide sequences of two previously cloned cDNAs that correspond to two different nonallelic Xenopus insulin genes (both of which are expressed in the adult pancreas) and (ii) a modification of the highly sensitive reverse transcription-polymerase chain reaction (RT-PCR) method developed in our laboratory, designated RNA template-specific PCR (RS-PCR), we now find that mRNAs for both Xenopus insulins I and II are present in mature (stage VI) oocytes but not in less-mature oocytes (stages I and IV) or in unfertilized eggs. The Xenopus insulin II gene is differentially expressed during early neurulation (stage 13), while only the insulin I gene is expressed at stage 21, when the neural tube is closing and cephalization is beginning. During later stages (i.e., stage 26) there is a region in the head that appears to be transcribing only the insulin I gene, while mRNAs for both insulins I and II are present in the body region. These findings show that the two nonallelic insulin genes are expressed differentially in Xenopus embryos in a stage- and region-specific manner; because appropriate receptors are also present, we suggest a role for insulin during early nervous system development well before the emergence of pancreatic beta cells.

Alleles↗