Biomedical subjects
Publications and source records attributed to J Nahmias.
To test the current explanation of the so-called floating drops phenomenon by the thinning and drainage of an interstitial film, we have produced such drops under low pressure. Our results show a lifetime of drops exceeding two h, which refutes previous results published in the literature. Copyright 1999 Academic Press.
This is a case report and review of the literature on primary melanoma of the cervix. There have been only 26 published cases of primary cervical melanoma and most are poorly documented and doubtful. The patients' ages ranged from 26 to 78 years old with a mean age of 55 +/- 13 years. The main presenting symptom was vaginal bleeding (83.0%). The majority of the patients, 88%, presented in stage I or II. Treatment varied from a simple excision of a cervical mass to a radical hysterectomy with lymph node dissection and adjuvant radiation or chemotherapy. Our patient presented with vaginal bleeding and was diagnosed as having stage IIa cervical melanoma. She underwent a radical hysterectomy, partial vaginectomy, and pelvic and paraaortic lymph node dissection. She received adjuvant radiation therapy and her survival was 29 months. The prognosis of primary cervical melanoma is usually poor and unpredictable. We recommend a radical hysterectomy and vaginectomy, if necessary, to obtain negative surgical margins of at least 2 cm. We advocate lymphadenectomy only for grossly positive nodes.
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This report presents the chromosomal localization of cadherin genes. Cadherins are cellular adhesion molecules. Since disturbance of intracellular adhesion is important for invasion and metastasis of tumor cells, cadherins are considered prime candidates for tumor suppressor genes. A variety of solid tumors show loss of heterozygosity of the long arm of chromosome 16, which is indicative of the potential location of tumor suppressor genes. Refined and new localizations of six cadherin genes (CDH3, 5, 8, 11, 13, and 15) to the long arm of chromosome 16 are shown. CDH15 was localized to 16q24.3, in a region that exhibits loss of heterozygosity in a number of sporadic breast cancer tumors. Previous localization of CDH13 (H-cadherin) to 16q24 suggested this gene as a tumor suppressor candidate in the 16q24.3 loss of heterozygosity region; however, refined mapping presented in this report localizes CDH13 proximal to this region. A human EST homologous to the chicken cadherin-7 was partially sequenced and found to represent a new human cadherin. This cadherin mapped to chromosome 18q22-q23, a region that exhibits loss of heterozygosity in head and neck squamous cell carcinomas. CDH16 was localized to 8q22.1, a region exhibiting loss of heterozygosity in adult acute myeloid leukemia.
We have previously reported the presence of marked immune dysregulation with a dominant Th2 profile, in a population of Ethiopian immigrants (ETH) in Israel heavily infected with helminths. In order to characterize better this immune dysregulation we studied by flow cytometry the expression of several activation markers on peripheral T cell populations, and lymphocyte apoptosis, in blood samples obtained from 63 'new' ETH (recently arrived), 18 'old' ETH (> 5 years since immigration) and 34 non-Ethiopian Israelis. The main findings in the 'new' ETH group in comparison with the non-Ethiopian controls were: (i) decreased CD4 and increased CD8 lymphocyte counts; (ii) elevated levels of activated T cells (CD3, CD4 and CD8) expressing HLA-DR; (iii) decreased levels of 'naive' CD4+ cells (CD45RA+), with increased levels of 'memory' CD4+ cells (CD45RO+); (iv) decreased numbers of CD28+ CD8+ lymphocytes; (v) marked increase in lymphocyte apoptosis. These T cell alterations and activation profile remained unchanged in 10 'new' ETH in whom the helminth infections persisted for 6-11 months. In contrast, in 18 'old' ETH, without helminth infections, the T cell activation profile was within the normal range. These findings suggest that chronic helminth infections may have a profound effect on the immune system of the host that disappears after eradication of these infections and adjustment to the new environment. It should therefore be taken into consideration for every immunomodulation therapy and especially in vaccine design and trials, in regions endemic for helminth infections.
Twenty-three unrelated patients with tuberous sclerosis have been screened for the presence of mutations in six regions of the TSC2 gene. Eight novel intragenic polymorphisms have been found, one in intron 36 and seven in intron 4, with the use of SSCP analysis. Four of these polymorphisms alter the recognition sequence of specific restriction enzymes and can be detected as RFLPs. Study in a random sample of unrelated individuals from Northern Greece, showed that these polymorphisms have mean observed and expected heterozygosity values of 0.2996 and 0.3349, respectively and could be useful for linkage analysis. It is most likely that the wild type alleles from two pairs of these polymorphisms are strongly associated. A 667 bp segment of intron 4 (954 bp) and an additional 75 bp of intron 36 (352bp) were sequenced, thus completing the sequence of both introns.
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Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the widespread development of distinctive tumors termed hamartomas. TSC-determining loci have been mapped to chromosomes 9q34 (TSC1) and 16p13 (TSC2). The TSC1 gene was identified from a 900-kilobase region containing at least 30 genes. The 8.6-kilobase TSC1 transcript is widely expressed and encodes a protein of 130 kilodaltons (hamartin) that has homology to a putative yeast protein of unknown function. Thirty-two distinct mutations were identified in TSC1, 30 of which were truncating, and a single mutation (2105delAAAG) was seen in six apparently unrelated patients. In one of these six, a somatic mutation in the wild-type allele was found in a TSC-associated renal carcinoma, which suggests that hamartin acts as a tumor suppressor.
Using a rotating magnet device, we observe the noncoalescence of droplets of certain liquids slightly put in contact with the surface of the same liquid. The droplets go into the vortex and coalesce, the resulting drop staying in equilibrium in this position. If the rotation of the liquid is stopped, the drop rests at the surface for more than 20 s, as if it were immiscible, without any relative motion.
The disease gene TSC1 has been genetically mapped to human chromosome region 9q34, in a 4-cM interval between the markers D9S149 and D9S114. Within this interval there is conflicting genetic evidence as to the finer localization of the gene. We have used finger-printing methods and hybridization to produce a 1.7-Mb overlapping clone map covering the TSC1 candidate region, with a single gap of 20 kb. We have localized 12 previously cloned genes and 17 genetic markers on this map and have confirmed the order of the genetic map. This deep set of overlapping clones is now ready to be used for candidate gene isolation, for transcription studies, or for sequencing.
A unified nomenclature for describing voltage-gated calcium channel genes is proposed. The terminology has been approved by the HUGO/GDB nomenclature committee.
The cellular and humoral immune responses of 41 hydatidosis patients, 12 healthy uninfected individuals, and seven patients with other parasitic diseases were determined using serologic and lymphoproliferative assays (LPAs), respectively. Echinococcal antigens were obtained by gel filtration of crude hydatid cyst fluid (HCF) on a Sephadex G-200 column. The fractions contained either a mixture of antigens A plus B or antigen B alone that was further enriched by boiling. All the hydatidosis patients responded positively by LPA to either crude or purified echinococcal antigens: 95% of them responded to either crude HCF, or a mixture of antigens A plus B and 83% to antigen B alone. The degree of the response to crude HCF (mean stimulation index [SI] = 75.3) was higher than that of purified antigens (SI = 39.1 for a mixture of antigens A plus B and SI = 36.9 for antigen B alone). No positive LPA response was obtained with the control groups. Serologic examinations showed that 78% of cases were positive by immunoblot, 73% by indirect hemagglutination, and 46% by immunoelectrophoresis. No correlation between the degree of cellular and humoral responsiveness to both crude and purified echinococcal antigens was observed. Nine of the 41 patients examined who were serologically negative also developed a high lymphoproliferative (LP) response to either crude or purified echinococcal antigens. The LP response remained positive over a long period after successful treatment. No relationship was observed between the results of treatment and the LP response. The present study indicates that the LPA could be used as an additional tool for the diagnosis of hydatid disease, particularly in seronegative cases, although it is unsuitable for effective monitoring treatment/surgery.
A human gene encoding a putative RNA helicase, designated DDX10, was identified 400 kb telomeric to the ataxia-telangiectasia gene at chromosome 11q22-q23. The predicted amino acid sequence shows very high similarity to a subgroup of DEAD-box RNA helicases involved in ribosome biogenesis. This novel gene encodes a 3.2-kb transcript in a variety of human tissues. A processed pseudogene of DDX10 was detected at chromosome 9q21-q22. We observed a rare trinucleotide repeat length polymorphism within the coding sequence of DDX10.
OBJECTIVES: Our purpose was (1) to assess the influence of delivery route on neonatal outcome in fetuses with gastroschisis and (2) to correlate ultrasonographic appearance of fetal bowel with immediate postnatal outcome. STUDY DESIGN: Forty-seven cases (1986 to 1994) were reviewed; three abortions and two stillbirths were excluded. Ultrasonographic appearance of fetal bowel (small bowel dilatation > 10 mm) was evaluated in 27 cases. RESULTS: Twenty-six infants (61.9%) were delivered vaginally and 16 (38.1%) by cesarean section (11 elective, 5 in labor). Delivery route was not significantly associated with indicators of neonatal outcome (rate of primary closure, postoperative complications, days of parenteral nutrition, days to oral feeding, hospital days, or mortality). When ultrasonographic appearance of fetal bowel was correlated with outcome, fetuses with prenatally dilated bowel had significantly more bowel edema at birth (p=0.038), longer operative time (p=0.013), and higher overall rate of postoperative complications (p=0.037). CONCLUSIONS: (1) Elective cesarean delivery does not improve neonatal outcome in infants with gastroschisis. (2) Abnormal ultrasonographic appearance of fetal bowel is associated with a more difficult repair and a higher overall incidence of postoperative complications.
The incidence and pathogenesis of right ventricular dysfunction in obstructive sleep apnoea (OSA) remains controversial. Using nuclear ventriculography, the prevalence of right ventricular dysfunction (RVD) was therefore determined in obese patients with OSA, as well as their clinical characteristics, arterial blood gas values, spirometry and sleep parameters. The reversibility of RVD was evaluated after long-term use of nasal continuous positive airway pressure (nCPAP). We studied 112 obese patients with OSA by nuclear ventriculography, 35 with RVD (Group 1), 77 without RVD (Group 2), and 14 patients without OSA as controls (Group 3). Repeat nuclear ventriculography was performed in seven patients who used nCPAP nightly for 6-24 months. The mean right ventricular ejection fractions (RVEF) were 31%, 47% and 44% in Groups 1, 2 and 3, respectively. Group 1 also had a lower left ventricular ejection fraction (LVEF) of 55 vs 63% in Group 2. The OSA groups did not differ in mean spirometric or arterial blood gas values. Group 1 had a lower mean nocturnal arterial oxygen saturation (Sa,O2) of 82 vs 87% in Group 2, and a longer apnoea duration of 22.3 vs 19.2 s. All but two patients in Group 1 had either awake alveolar hypoventilation or an apnoea + hypopnoea index > 40 disordered breathing events.h-1. Repeat nuclear ventriculography after nCPAP revealed an increase in RVEF from 30 to 39%. In conclusion, right ventricular dysfunction is common in obstructive sleep apnoea, but it is reversible with nasal continuous positive airway pressure treatment and appears to be related to nocturnal oxygen desaturation.
Tuberous sclerosis (TSC) is an autosomal dominant disorder characterized by seizures, mental retardation, and hamartomatous lesions. Although hamartomas can occur in almost any organ, they are most common in the brain, kidney, heart, and skin. Allelic loss or loss of heterozygosity (LOH) in TSC lesions has previously been reported on chromosomes 16p13 and 9q34, the locations of the TSC2 and TSC1 genes, respectively, suggesting that the TSC genes act as tumor-suppressor genes. In our study, 87 lesions from 47 TSC patients were analyzed for LOH in the TSC1 and TSC2 chromosomal regions. Three findings resulted from this analysis. First, we confirmed that the TSC1 critical region is distal to D9S149. Second, we found LOH more frequently on chromosome 16p13 than on 9q34. Of the 28 patients with angiomyolipomas or rhabdomyomas, 16p13 LOH was detected in lesions from 12 (57%) of 21 informative patients, while 9q34 LOH was detected in lesions from only 1 patient (4%). This could indicate that TSC2 tumors are more likely than TSC1 tumors to require surgical resection or that TSC2 is more common than TSC1 in our patient population. It is also possible that small regions of 9q34 LOH were missed. Lastly, LOH was found in 56% of renal angiomyolipomas and cardiac rhabdomyormas but in only 4% of TSC brain lesions. This suggests that brain lesions can result from different pathogenic mechanisms than kidney and heart lesions.
A fluorescence in situ hybridization map of distal human chromosome 9q has been produced by mapping cosmid clones to metaphase chromosomes with balanced reciprocal translocations. This is a very accurate method of mapping, as clones are localized by their position with respect to the breakpoint in addition to cytogenetic banding. By using three lymphoblastoid cell lines with translocation breakpoints within 9q34, we have localized 18 genes and 14 DNA markers to one of four intervals on the chromosome. Cosmid contigs exist around 16 of these genes and 12 of these markers. A further 43 contigs have also been mapped, but they are as yet anonymous.