In vivo 1H magnetic resonance imaging and spectroscopy of the rat spinal cord using an inductively-coupled chronically implanted RF coil.

An inductively coupled, chronically implanted short-solenoid coil was used to obtain in vivo localized 1H NMR spectra and diffusion-weighted images from a rat spinal cord. A 5 x 8 mm two-turn elliptically shaped solenoid coil was implanted in rats at the site of a T-12 vertebral-level laminectomy. Excitation was achieved solely by a 3 x 3 cm external surface coil, and signal detection was achieved by inductively coupling the external coil to the implanted coil. The image signal-to-noise ratio (SNR) obtained with the inductively-coupled implanted coil was compared with that obtained using a linear or a quadrature external surface coil. The implanted coil provided a gain by over a factor of 3 in SNR. The implanted coil was used to measure localized 1H spectra in vivo at the T13/L1 spinal-cord level within a 1.85 x 1.85 x 4.82 mm (16.5 microL) volume. With 256 averages, a approximately 3-s repetition delay and respiratory gating, a high-quality spectrum was acquired in 13 min. In addition, water translational diffusion was measured in three orthogonal directions using a stimulated-echo imaging sequence, with a short echo time (TE), to produce a quantitative map of diffusion in a rat spinal cord in vivo.

Cryptorchidism as a caudal developmental field defect. A new description of cryptorchidism associated with malformations and dysplasias of the kidneys, the ureters and the spine from T10 to S5.

Cryptorchidism is a feature of abnormalities in the hypothalamo-pituitary-testicular axis, and almost all disorders of sexual differentiation in which a testis is present. We found cryptorchidism to be associated with malformations and dysplasias of the kidneys, the ureters and the spine from T10 to S5. The description of this association is new. The association was seen in 18% of cryptorchid boys younger than 3 years of age in a department of paediatric surgery, in 34% of cryptorchid foetuses who died in the third trimester, in 65% of cryptorchid patients with imperforate anus, and in all individuals with tritonmelia, the male variant of sirenomelia. Sirenomelia/tritonmelia is an extreme degree of abnormal differentiation of the caudal developmental field, also called caudal dysplasia, the caudal regression syndrome and the caudal regression malformation sequence. Caudal developmental field defects were also the predominant abnormalities in the other groups of patients. Thus, cryptorchidism may be a feature of abnormal differentiation of the caudal developmental field. Position and histology of the undescended testes of the patients included in the association were similar to in cryptorchidism in general. In the literature the association was reported in 5-10% of boys considered to suffer from cryptorchidism only. Furthermore, our observations are concordant with recent theories about cryptorchidism. Consequently, we propose that cryptorchidism in general may be a caudal developmental field defect. Study of cryptorchid patients exhibiting malformations or dysplasias of the kidneys, the ureters or the spine from T10 to S5 is essential in order to isolate new genetic disorders and to spot environmental factors causing cryptorchidism.

Absence of human placental lactogen and placental growth hormone (HGH-V) during pregnancy: PCR analysis of the deletion.

Human placental lactogen (HPL) is produced in large amounts in normal pregnancies. We report a pregnancy with complete lack of HPL and the placental variant of the human growth hormone HGH-V. The pregnancy resulted in a severely growth-retarded but otherwise normal male baby. PCR analysis of DNA extracted from the placenta showed that the HPL encoding genes hPL-4 and hPL-3 were deleted along with the human growth hormone variant gene (hGH-V), which is located between these two active hPL genes and also expressed in the normal placenta. Of the five members of this multigene family, hGH-N, which is expressed in the pituitary gland, and hPL-1, a presumed pseudogene, were left intact. The latter (hPL-1) was expressed as RNA transcripts only at very low levels as is usually reported in normal pregnancies. Analysis of the parents' DNA showed that both of them carried a different heterozygous deletion at the 3' end of the hGH/hPL locus.

[Cryptorchidism in boys with anal atresia]. / Kryptorkisme hos drenge med anal atresi.

In a retrospective study of the case reports of 136 boys who were operated on for an imperforate anus and who survived at least 18 months, cryptorchidism was the most common associated anomaly, involving 26 cases (19%). The higher the level of the anorectal malformations, the higher was the incidence of cryptorchidism. The incidence of renal and ureteric malformations and dysplasias showed a parallel tendency. The incidence of vertebral malformations and dysplasias in the T10-S5 area was low among patients with a covered anus or a perineal fistula. Cryptorchidism was found to be associated with urological and with T10-S5 vertebral malformations and dysplasias. Recognition of this association is probably new. The histopathological findings of testicular biopsy specimens and the location of the undescended testes in patients with an imperforate anus showed the same pattern as seen in undescended testes from patients with cryptorchidism only. These findings, together with the existing literature on the subject, indicate that further studies on the association of cryptorchidism, urological, and T10-S5 vertebral malformations and dysplasias may be important for a better understanding of cryptorchidism in general.

[Laparoscopy in 100 consecutive patients with 128 impalpable testes]. / Laparoskopi af 100 konsekutive patienter med 128 ikkepalpable testes.

A cohort of 100 patients underwent laparoscopy for 128 impalpable testes. They ranged in age from 2.7 to 19.3 years (median 10.8 years). There were no complications associated with laparoscopy. In 50% of the cases either blindending cord structures above the internal inguinal ring or intra-abdominal testes were identified; in the remainder, cord structures could be seen passing through the ring, indicating an intracanalicular testis. The impalpable testis was absent in 77% of patients with a contralateral scrotal testis. A seminoma was found in one 18.6-year-old patient with bilateral cryptorchidism. No intratubular germ cell neoplasia (carcinoma in situ) was proved. Germ cell hypoplasia or aplasia was demonstrated in 95% of cases with testicular parenchyma. We recommend laparoscopy as a safe procedure which leads to a diagnosis in patients with impalpable testes; the advent of laparoscopic procedure makes definitive treatment possible in about 50% of such cases.

Quantitative histology of germ cells in the undescended testes of human fetuses, neonates and infants.

PURPOSE: We investigated the number of germ cells per tubular cross section and testicular weight in cryptorchid fetuses, neonates and infants, and characterized additional abnormalities. MATERIALS AND METHODS: Our series comprised 35 fetuses and 58 boys with cryptorchidism, and 22 normal fetuses and 25 normal boys. Age ranged from 28 weeks of gestation to 3 years. RESULTS: Cryptorchid fetuses had reduced germ cells per tubular cross section values and lower testicular weights. Values were reduced in cryptorchid boys without a symptomatic inguinal hernia. If a hernia was present, values were normal in the first year of life but decreased at age 1 to 3 years. Malformations or dysplasia of the kidneys, ureter or T10 to S5 vertebrae were present in 34% of the cryptorchid fetuses and 18% of the cryptorchid boys without a symptomatic inguinal hernia. CONCLUSIONS: Our study suggests a reduced number of germ cells in undescended testes from week 28 of gestation and germ cell hypoplasia as a consequence of continued postnatal undescended testicular position. Cryptorchidism may result from abnormal development of the caudal developmental field.

Cryptorchidism in boys with imperforate anus.

In a retrospective study of the case reports of 136 boys who were operated on for an imperforate anus and who survived at least 18 months, cryptorchidism was the most common associated anomaly, involving 26 cases (19%). The higher the level of the anorectal malformations, the higher was the incidence of cryptorchidism. The incidence of renal and ureteric malformations and dysplasias showed a parallel tendency. The incidence of vertebral malformations and dysplasias in the T10-S5 area was low among patients with a covered anus or a perineal fistula. Cryptorchidism was found associated with urological and with T10-S5 vertebral malformations and dysplasias. Recognition of this association is probably new. The histopathological findings of testicular biopsy specimens and the location of the undescended testes in patients with an imperforate anus showed the same pattern as seen in undescended testes from patients with cryptorchidism only. These findings, together with the existing literature on the subject, indicate that further studies on the association of cryptorchidism, urological, and T10-S5 vertebral malformations and dysplasias may be very helpful toward a better understanding of cryptorchidism in general.

Laparoscopy in 100 consecutive patients with 128 impalpable testes.

OBJECTIVE: To investigate the value of laparoscopy in boys with impalpable testes, to carry out a histological examination of testicular biopsies or orchidectomy specimens, and to present a clinical description of boys with impalpable testes. PATIENTS AND METHODS: One hundred consecutive patients underwent laparoscopy for 128 impalpable testes. They ranged in age from 2.7 to 19.3 years (median 10.8). Histological examination was performed on 39 testicular biopsies, nine primarily orchidectomized testes and 13 tissue samples from the end of blind-ending vessels and vasa deferentia. Any additional diagnoses to that of impalpable testes were recorded. RESULTS: There were no complications associated with laparoscopy and the procedure clarified the situation in all patients. In 50% of patients either blind-ending cord structures above the internal inguinal ring or intra-abdominal testes were identified; in the remainder, cord structures could be seen passing through the ring, indicating an intracanalicular testis. The impalpable testis was absent in 77% of patients with a contralateral scrotal testis. A seminoma was found in one 18.6-year-old patient with bilateral cryptorchidism. No intratubular germ cell neoplasia (carcinoma in situ) was found. Germ cell hypoplasia or aplasia was demonstrated in 95% of patients with testicular parenchyma. Additional diagnoses were made in 49% of patients with bilaterally undescended testes (one or both of which were impalpable). CONCLUSION: We recommend laparoscopy as a safe procedure which leads to a diagnosis in patients with impalpable testes; the advent of laparoscopic procedures makes definitive treatment possible in about 50% of such patients. Open procedures will be indicated only to ascertain the quality and treatment of intracanalicular testes.

Examination for intratubular germ cell neoplasia at operation for undescended testis in boys.

A total of 843 consecutive boys (median age 12.7 years) who had undergone testicular biopsy at operation for undescended testis was followed into adulthood (median age 25.2 years) to examine for testicular germ cell neoplasia. Five cases of testicular germ cell neoplasia were identified, including 1 nonseminoma of the contralateral testis, which had been treated before surgery for an undescended testis, 1 nonseminoma found at followup, 1 seminoma and 2 intratubular germ cell neoplasms. Of the later 3 patients 1 had a 45,X/46,XY karyotype and 2 had abnormal external genitalia. Previous testicular biopsy from the patient in whom nonseminoma was noted at followup showed Sertoli cells only. We recommend that testicular biopsy be performed at operation for undescended testis in boys with abnormal sex chromosomes, particularly 45,X/46,XY karyotype, and in those with abnormal external genitalia. The pattern of Sertoli cells only in biopsies from boys does not preclude the occurrence of testicular cancer in adulthood.

Acidic residues are involved in substrate recognition by two soluble protein tyrosine phosphatases, PTP-5 and rrbPTP-1.

The mechanisms for substrate recognition by two cytoplasmic protein tyrosine phosphatases, PTP-5 and rrbPTP-1, were investigated. Phosphorylation sites on tyrosine-phosphorylated casein, a model PTP substrate, were characterized. Two peptides based on casein phosphorylation sites and one peptide based on the tyrosine phosphorylation site of reduced, carboxamidomethylated and maleylated (RCM) lysozyme were tested as PTP substrates. The three peptides were dephosphorylated by PTP-5 and rrbPTP-1 at rates comparable to those of the corresponding sites on the intact proteins. This indicates that peptides based on the two model PTP substrates, casein and RCM-lysozyme, contained all or most of the structural information necessary for PTP-5 and rrbPTP-1 substrate recognition. Structural elements required for substrate recognition by PTP-5 and rrbPTP-1 were also investigated. Km values for dephosphorylation of three simple aromatic phosphate esters (phosphotyrosine, p-nitrophenyl phosphate, and phenyl phosphate) by rrbPTP-1 were about 5000-fold higher than those obtained for the peptide and protein substrates. This indicates that recognition of protein and peptide substrates involves structural elements in addition to the phosphate group and the aromatic tyrosine ring of phosphotyrosine. Analysis of the effects of truncations and Ala for polar substitutions on the reactivity with PTP-5 and rrbPTP-1 of peptides based on casein, RCM-lysozyme, and angiotensin II indicated that Asp or Glu within the first five residues on the N-terminal side of phosphotyrosine increased peptide reactivity with both PTP's. Asn residues were unable or only weakly able to substitute for Asp residues.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of an inductively coupled implanted coil with optimized surface coils for in vivo NMR imaging of the spinal cord.

A study was performed to determine whether an implanted, inductively coupled nuclear magnetic resonance (NMR) imaging spine coil could provide a significant gain in signal-to-noise ratio (SNR) on images of the spinal cord relative to the SNR of optimized surface coils. Implanted coils were surgically affixed to the upper lumbar spine (first lumbar through third lumbar vertebrae) in a total of four adult cats. The implanted coil was inductively coupled to an external 12 x 12 cm square surface coil that was mounted on a 14-cm diameter Plexiglas cradle (Townsend Industries, Des Moines, IA). Two similar cradles were prepared with transmit-only 12 x 12 cm surface coils and either a receive-only 6 x 6 cm square surface coil or a receive-only quadrature coil pair (two 4 x 6 cm coils overlapped slightly to minimize their mutual inductance) with the same surface area (6 x 6 cm). A total of five single-slice, T1-weighted spin-echo images (TR = 500 ms, TE = 30 ms, 4-mm slice thickness) were acquired from a 1-liter saline phantom and from the second lumbar spinal level in an adult cat with a normal, uninjured spinal cord. On the spinal cord images, the quadrature coil exhibited a factor of 1.65 increase in SNR relative to the single-turn surface coil, whereas the implanted coil achieved a factor of 2.19 increase in SNR. The improved SNR for the quadrature and implanted coils was observed as a dramatic improvement in the clarity of the images.(ABSTRACT TRUNCATED AT 250 WORDS)

Double resonant quadrature birdcage.

The combined acquisition of proton images and localized spectra is considered essential to the application of NMR techniques to human and animal research. The ideal imaging/spectroscopy coil for our purposes would be one that provides the highest possible signal-to-noise, high homogeneity, and operation on two or more frequencies without retuning requirements or cable changes. To address these needs we have developed a quadrature double-tuned birdcage. We have incorporated our earlier work on the transformer coupled double-tuned surface coil into the birdcage structure by placing two birdcages in a coaxial configuration. This structure resonates at 34.6 MHz (phosphorus resonance at 2.0 T) and 85.5 MHz (proton resonance at 2.0 T). The quadrature performance of this coil for phosphorus was excellent, with a signal-to-noise that was 133% of our linear reference. The proton performance was less efficient, with a signal to noise that was 67% of our linear reference, but still quite sufficient for imaging. A phosphorus spectra and proton image of a rat abdomen are shown.

pNiXa, a Ni(2+)-binding protein in Xenopus oocytes and embryos, shows identity to Ep45, an estrogen-regulated hepatic serpin.

A Ni(2+)-binding protein (pNiXa, 45 kD, pI 8.5) discovered in Xenopus embryos, was isolated from oocytes. Based on amino acid sequences, pNiXa belongs to the serpin superfamily and shows identity to the cDNA sequence of Ep45, an estrogen-regulated hepatic serpin that contains an (HX)n-motif found in eukaryotic transcription factors. Nondenatured pNiXa, purified by Ni-affinity chromatography, inhibited bovine alpha-chymotrypsin. The presence of pNiXa in embryos when they are susceptible to Ni2+, the high avidity of pNiXa for Ni2+, and the (HX)n-motif point to pNiXa as a molecular target of Ni(2+)-teratogenesis.

A protein isolated from Brucella abortus is a Cu-Zn superoxide dismutase.

Brucella abortus contains a protein that elicits an antigenic response in cattle previously exposed to the organism. The amino acid sequence of the recombinant form of this antigenic protein was determined by gas-phase sequencing of the pyridylethylated protein and its peptides obtained by digestion with cyanogen bromide (CNBr), clostripain, and Staphylococcus aureus V8 protease. The Brucella protein demonstrated 53.6% identity with the Cu-Zn superoxide dismutase (SOD) from Photobacterium leiognathi. Residues essential for metal coordination and enzymatic activity and cysteines required for the formation of the intrasubunit disulfide bridge of Cu-Zn SOD were conserved in the Brucella protein. also exhibited SOD activity that was inhibited by cyanide, which is characteristic of a Cu-Zn SOD. Brucella abortus Cu-Zn SOD is the second prokaryotic Cu-Zn SOD to be sequenced, and the fifth found in prokaryotes. The high degree of conservation between Photobacterium and Brucella Cu-Zn SOD supports the hypothesis of a separately evolved prokaryotic and eukaryotic Cu-Zn SOD gene.

Increase in serum digoxin concentration produced by quinidine does not increase the potential for digoxin-induced ventricular arrhythmias in dogs.

Chronic treatment of dogs with digoxin alone, quinidine alone and digoxin in combination with quinidine was initiated in dogs to assess changes in arrhythmogenic potential associated with the quinidine-induced increase in serum digoxin concentration observed during combined digoxin and quinidine treatment. The arrhythmogenic potential of digoxin was evaluated through the use of the acetylstrophanthidin (AcS) tolerance test. AcS was infused at a rate of 5 micrograms/kg/min until ventricular arrhythmias occurred during a drug-free period and during chronic treatment with digoxin, quinidine and digoxin plus quinidine. The dose of AcS required to initiate ventricular arrhythmias is inversely related to the arrhythmogenic potential of digoxin present at the time of AcS infusion. Administration of quinidine alone in two different dosage regimens produced serum quinidine concentrations of 5.99 +/- 1.18 and 2.99 +/- 0.43 micrograms/ml and significantly increased AcS tolerance, whereas digoxin alone, over a wide range of serum digoxin concentrations, significantly decreased AcS tolerance. This decrease in AcS tolerance was linearly related to the serum digoxin concentration. The addition of quinidine treatment to animals receiving digoxin resulted in a significant elevation in the steady-state serum digoxin concentration. However, the AcS tolerance determined during the elevated serum digoxin concentration induced by quinidine was greater than that determined during treatment with the same dose of digoxin alone. Thus, quinidine administration to animals receiving digoxin resulted in a significant increase in the steady-state serum digoxin concentration but did not increase the arrhythmogenic potential of digoxin over that observed during treatment with the same dose of digoxin alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Two cases of congenital vascular malformations proved by post-mortem arteriography. Case reports.

Post-mortem arteriography, properly carried out, visualizes the whole extent of the arterial vascular system. The intimate relationship of parenchymatous organs to their arterial supply makes it possible to identify and localize the individual structure, even where there are abnormalities. Arteriography has never been methodically applied to post-mortem examinations of fetuses and perinates. Two cases selected from a material of 100 consecutive fetuses and perinates thus examined document that even though the external appearance of fetuses and perinates is normal, there may be severe internal congenital malformations.

Computer-assisted determination of protein concentrations from dye-binding and bicinchoninic acid protein assays performed in microtiter plates.

The bicinchoninic acid protein assay was scaled down to operate in the wells of microtiter plates. The total volume of the assay was reduced to 210 microliters and required only 10 microliters of sample per assay. The assay can be rapidly performed and then read with a plate reader. The analysis of the data was performed with a microcomputer interfaced with the reader. A computer program was developed to analyze the data from the bicinchoninic acid assay as well as the dye-binding assay at either the high or low protein concentration ranges. Based upon the absorbance values of the standards, the program computed a linear regression formula which was then used to calculate the concentrations of the sample proteins. A series of assays performed using bovine serum albumin, alpha-chymotrypsin and gamma globulin demonstrated that the scaled down bicinchoninic acid assay produced linear absorption versus concentration data with average correlation coefficients between 0.9967 and 0.9940 at the high and low concentration ranges respectively. The protein-to-protein variation and proper selection of either protein assay based upon the presence of interfering materials was considered.